??DIAGNOSIS—DS--I think cervical ectopy with acetic acid applied

Petechiae of the cervix in woman diagnosed with trichomoniasis. This is commonly referred to as a “strawberry cervix”.

Herpes zoster (shingles) in the lower back region.

Frothy yellow vaginal discharge in a woman with vaginitis and trichomoniasis.

Large, non-painful ulcers on the shaft and base of the penis in a man with primary syphilis. 

Large, non-painful ulcers on the shaft and base of the penis in a man with primary syphilis. 

Large, non-painful ulcers on the shaft and base of the penis in a man with primary syphilis. 

Papular lesions with collarette of scale on the palms of both hands caused by secondary syphilis.

Large primary syphilis ulcer on distal shaft of penis with marked edema.

Large primary syphilis ulcer on distal shaft of penis with marked edema.

Clusters of vesicles with surrounding erythema on the left buttocks and gluteal fold region caused by recurrent herpes simplex virus (HSV) infection.

Cluster of vesicular lesions with surrounding erythema in perianal/gluteal region caused by herpes simplex virus (HSV) infection.

Oral HSV

Extensive vesicular lesions involving all regions of lips in a man with first episode (primary) oral herpes simplex virus (HSV) infection.

Ulcerated lesion on shaft of penis just inferior to ventral glans caused by recurrent herpes simplex virus (HSV) infection. 

Cluster of vesicles on the shaft of the penis caused by recurrent herpes simplex virus (HSV) infection.

Linear cluster of scabbed resolving herpes simplex virus (HSV) lesions on shaft of penis.

Multiple hypopigmented healing genital herpes lesions on the shaft of the penis. 

Extensive superficial ulceration on the glans of the penis caused by herpes simplex virus infection.

Dense, extensive clusters of vesicles with surrounding erythema on right flank and abdominal region caused by herpes zoster (shingles).

Healing herpes zoster (shingles) lesions on right flank and abdominal region.

Ulcerated lesion in the perianal region caused by recurrent herpes simplex virus (HSV) infection.

Ulcerated, oval lesion on the left gluteal region caused by recurrent herpes simplex virus (HSV) infection. 

Herpetic whitlow

Annular lesion with white raised, lacy/reticulated border (often referred to as Wickam's striae) and darker center on the glans penis caused by lichen planus.

Annular lesion with white raised, lacy/reticulated border (often referred to as Wickam's striae) and darker center on the shaft of the penis caused by lichen planus.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), flesh-colored bumps in rows around the corona of the penis.

Multiple raised papular lesions on penis and scrotum consistent with condylomata lata in a man with secondary syphilis.

Papular rash with scale on the palm of the right hand caused by secondary syphilis.

Papular rash with scale on the sole of the right foot caused by secondary syphilis.

Multiple extensive vulvar and labial ulcerations (with surrounding ring of erythema) caused by first-episode (primary) herpes simplex virus (HSV) infection.

Multiple perianal ulcerated lesions with surrounding ring of erythema caused by herpes simplex virus (HSV) infection.

Solitary ulcer on lower left labia majora caused by recurrent herpes simplex virus (HSV) infection. 

Cluster of vesicles and ulcerated lesions on vulva caused by herpes simplex virus (HSV) infection

Multiple ulcerated lesions on right labia majora caused by herpes simplex virus (HSV) infection. 

Cluster of vesicles with surrounding erythema on suprapubic region caused by recurrent herpes simplex virus (HSV) infection. 

Extensive ulcerations on labia caused by herpes simplex virus (HSV) infection.

Linear superficial ulceration in lower vulvar/perianal region caused by recurrent herpes simplex virus (HSV) infection.

Diffuse, erythematous macular rash on back caused by secondary syphilis.

Diffuse, erythematous macular rash on anterior chest and abdomen caused by secondary syphilis.

Large, moist, verrucous, plaque-like lesions in gluteal folds cause by secondary syphilis (condylomata lata).

Perianal wart after freezing with liquid nitrogen.

Perianal warts.

Painful vesicular rash on left anterior thigh caused by herpes zoster (shingles). The rash occurred in the distribution of the anterior femoral cutaneous nerve (L2 and L3).

Gram stain of urethral discharge specimen showing clusters of intracellular gram-negative diplococci, which was diagnostic for gonorrhea.

Ulcerated solitary lesion at corner of mouth caused by herpes simplex virus, type 2 (HSV-2).

Erythematous, pruritic rash with a well-defined border involving the scrotum and bilateral upper inner thigh region caused by tinea cruris.

Large penile ulcer with exudate caused by primary syphilis.

Pruritic erythematous papules on right wrist caused by scabies.

Left-sided testicular and epididymal pain and swelling caused by epididymitis. Urine nucleic acid amplification testing was positive for Neisseria gonorrhoeae.

Left-sided testicular and epididymal pain and swelling caused by epididymitis. Urine nucleic acid amplification testing was positive for Neisseria gonorrhoeae.

Extensive penile swelling due to bacterial soft tissue infection. 

Papular genital warts clustered on the left side and septum (midline) of the scrotum.

Multiple painful vesicles and ulcers with an erythematous and edematous base on the right labia caused by herpes simplex virus (HSV) infection.

Diffuse, erythematous macular rash as shown on on arms and palms in a man with secondary syphilis.

Group of vesicles and shallow ulcers with surrounding erythema located on the base of his penis and suprapubic region in a man with genital herpes simplex virus (HSV) infection. Several of the lesions in the suprapubic regions have formed a scab as part of the healing process.

Painful small, tender, ulcers on the shaft and base of the penis in a man with herpes simplex virus type 1 (HSV-1) infection.

Non-tender, indurated, penile ulcer in a man with primary syphilis.

Non-tender ulcer on the tongue in a man with primary syphilis. 

Gonococcal urethritis. Patient with purulent urethral discharge and Gram stain showed intracellular gram-negative diplococci.

HSV-2 on penis. Patient had presents c/o slightly tender genital ulceration on the right ventral aspect of glans.

Annular lichen planus on the glans of the penis. The region involved is slightly raised with a whitish ring-shaped border.

Secondary syphilis and multiple oral mucous patches. These appear as painless, oval, slightly ulcerated lesions on the ventral surface of the tongue. These lesions are a darker pink than the normal surrounding tissue and they contain abundant spirochetes.

Multiple erythematous, plaques with scales on the penis diagnosed as psoriasis. There were also psoriasis lesions on the extensor surface of the elbows.

Large erythematous, plaque with scaling on the extensor surface of the right elbow. There were also multiple psoriasis lesions on the penis.

Psoriasis with erythematous patches on the penis and inguinal region. This type of psoriasis that develops in the genital and inguinal region is referred to as inverse psoriasis, or flexural psoriasis.

Psoriasis with erythematous patch in the left inguinal region. This type of psoriasis that develops in the genital and inguinal region is referred to as inverse psoriasis, or flexural psoriasis.

Psoriasis with erythematous patch in the bilateral inguinal region. This type of psoriasis that develops in the genital and inguinal region is referred to as inverse psoriasis, or flexural psoriasis.

Psoriasis with erythematous patch in the perianal and medial gluteal region. This type of psoriasis that develops in the genital region is referred to as inverse psoriasis, or flexural psoriasis.

Fixed-drug eruption with a large ulcerated and hypopigmented area on the glans of the penis; the fixed-drug eruption occurred after starting doxycycline for the treatment of urethritis.

Secondary syphilis. Diffuse erythematous Macular rash on body as shown on chest.

Secondary syphilis. Diffuse erythematous Macular rash on body as shown on back.

Herpes-simplex virus type 2 (HSV-2) infection on inner thigh manifesting with a cluster of vesicles on an erythematous base.

Condylomata lata lesions on the scrotum in a man with secondary syphilis.

Condylomata lata lesions on the scrotum in a man with secondary syphilis.

Gonorrhea with purulent urethral discharge.

Gonorrhea with purulent urethral discharge.

Primary and secondary syphilis. This man had an overlapping penile ulcer (primary syphilis and multiple maculopapular lesions on penis and body (secondary syphilis).

Tinea versicolor (pityriasis versicolor) manifesting as hyperpigmented, macular lesions on the chest, shoulders, and back.

Tinea versicolor (pityriasis versicolor) manifesting as hyperpigmented, macular lesions on the chest, shoulders, and back.

Primary syphilis lesion on penis with ulcer and exudate

Purulent urethral discharge caused by gonorrhea.

Potassium hydroxide (KOH) skin scraping as viewed under a microscope from man with tinea versicolor. The fungal organisms are visible as round yeast forms (in clusters) and as short branched filaments. The combination of these two features is often described as a “spaghetti and meatballs” appearance.

Tinea versicolor on back (also referred to as pityriasis versicolor). Note patches of skin that are red-brown in color, scaling, and darker than the surrounding unaffected skin.

Tinea versicolor on right chest region (also referred to as pityriasis versicolor). Note patches of skin that are red-brown in color, and darker than the surrounding unaffected skin.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), non-tender, flesh-colored bumps in rows around the corona of the penis.

Secondary syphilis and multiple oral mucous patches. These appear as painless, oval, slightly ulcerated lesions on the ventral surface of the tongue. The most prominent patch is the dark oval region on the back left side of the tongue. These lesions are a darker pink than the normal surrounding tissue, and they contain abundant spirochetes.

Multiple erythematous, plaques with scales on the penis diagnosed as psoriasis. There were also psoriasis lesions on the extensor surface of the elbows.

Multiple small, painful ulcerations with surrounding erythema on the penile shaft in a man with herpes simplex virus type 1 (HSV-1).

Hypopigmented areas at base of penis and higher up on the shaft of the penis caused by vitiligo.

High-grade squamous intraepithelial lesion as viewed in anal canal with high-resolution anoscopy (HRA) and application of acetic acid. Not note punctuation (white arrow). The punctuation, which appears as small erythematous lesions in a dotted patter, represents an end-on view of dilated capillary vessels.

High-grade squamous intraepithelial lesion as viewed in anal canal with high-resolution anoscopy (HRA) and application of acetic acid. Not note punctuation (white arrow). The punctuation, which appears as small erythematous lesions in a dotted patter, represents an end-on view of dilated capillary vessels.

Extensive high-grade squamous intraepithelial lesion (HSIL) in perianal region in a man with HIV.

Extensive high-grade squamous intraepithelial lesion (HSIL) in intra-anal region in a man with HIV.

Large intra-anal condyloma in a man with HIV (as seen through anoscopy examination).

Intra-anal condyloma after ablation with hyfrecation in a man with HIV (as seen through anoscopy examination).

Multiple peri-anal condyloma in a man with HIV.

Multiple intra-anal condyloma in a man with HIV as seen through anoscopy examination.

Perianal high-grade squamous intraepithelial lesion (HSIL) in a man with HIV.

Perianal high-grade squamous intraepithelial lesion (HSIL) in a man with HIV.

Large mass of intra-anal warts in a man with HIV.

Extensive perianal warts in a man with HIV.

Secondary syphilis. Diffuse erythematous Macular rash on body as shown on chest and back (side view).

Cluster of superficial ulcerations with slight surrounding erythema present in the lower vaginal/perianal region (blue arrows) caused by recurrent herpes simplex virus (HSV) infection.

Ulcerated lesion at the base of the scrotum caused by herpes simplex virus (HSV). 

Multiple ulcerated lesions on the lower lip caused by recurrent oral herpes simplex virus (HSV) infection.

Extensive perianal warts in a man.

Epididymitis. Marked swelling in the right epididymis, scrotum, and testicle.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), non-tender, flesh-colored bumps in rows around the corona of the penis.

Extensive genital warts on the cervix.

Angiokeratomas (or Fordyce angiokeratomas). This man had chronic multiple small red-dark purple, non-tender papular lesions on the scrotum.

Scrotal cellulitis (with severe edema and bullous lesions) in a man with acute lymphocytic leukemia (ALL) and neutropenia; he was diagnosed with necrotizing fasciitis (Fournier’s gangrene). 

Suprapubic abscess and cellulitis caused by methicillin-resistant Staphylococcus aureus (MRSA).

Molluscum contagiosum papular lesion of the penile shaft in a man with HIV. These lesions have the characteristic dome shape (with central umbilication).

Genital scabies manifesting as pruritic, erythematous lesions on the glans of the penis.

Skin scraping as viewed under microscope showing a scabies mite with multiple eggs; this skin scraping was taken from a patient with crusted scabies and AIDS.

Genital scabies manifesting as pruritic, nodular lesions on the ventral surface of the scrotum.

Cellulitis and severe edema of penis, with necrotic tissue at the base of penis. The tissue necrosis at base of penis resulted from a retained metal cock ring; this photograph is taken after the cock ring had been cut and removed.

Kaposi’s sarcoma in a man with HIV and AIDS. The Kaposi’s sarcoma manifested as purple-red nodular circumferential lesions around the corona of the penis.

Kaposi’s sarcoma of the penis and scrotum in a patient with AIDS. The Kaposi’s sarcoma has infiltrated into the deeper genital tissues, causing marked scrotal and penile edema. In addition, there is significant destruction of the skin tissue overlying the scrotum and the base of the penis.

Squamous cell carcinoma of the anal and perianal region in a patient with HIV and advanced immunosuppression.

Extensive penile warts in a man with HIV and advanced immunosuppression.

Severe allergic reaction with marked penile edema. The allergic reaction was to female partner's contraceptive silocone cervical cap.

Severe allergic reaction with marked penile edema. The allergic reaction was to female partner's contraceptive silocone cervical cap.

Severe allergic reaction with marked penile edema. The allergic reaction was to female partner's contraceptive silocone cervical cap.

Condylomata lata in man with secondary syphilis. He presented with moist, raised warty papules, most prominent in the left-sided perianal region (blue arrows). Darkfield microscopy showed abundant spirochetes.

Vulvar condylomata lata in a woman with secondary syphilis. This photograph shows multiple vulvar and perianal papular verrucous-appearing lesions and two large nodular vulvar lesions. Abundant spirochetes were observed on microscopy.

Vulvar condylomata lata in a woman with secondary syphilis. This photograph shows multiple vulvar and perianal papular verrucous-appearing lesions and two large nodular vulvar lesions. Abundant spirochetes were observed on microscopy.

Fixed-drug eruption on glans of penis after taking trimethoprim-sulfamethoxazole. The eruption manifested as severe edema on the shaft of the penis below the glans and vesiculo-bullous lesions on the glans.

Fixed-drug eruption on glans of penis after taking trimethoprim-sulfamethoxazole. The eruption manifested as severe edema on the shaft of the penis below the glans and vesiculo-bullous lesions on the glans.

Fixed-drug eruption on glans of penis after taking trimethoprim-sulfamethoxazole. The eruption manifested as severe edema on the shaft of the penis below the glans and vesiculo-bullous lesions on the glans.

Multiple warts on the shaft of the penis. 

Patches of pseudomembranous candidiasis in pharynx and soft palate in a man with HIV.

Wart on penis treated with over-the-counter wart remedies that resulted in erythema and contact dermatitis. 

A cluster of warts on the distal shaft of the penis just proximal the glans.

Multiple perianal and intra-anal warts.

Multiple perianal and intra-anal warts.

In the baseline state of a healthy vaginal microbiome, Lactobacillus species are dominant.

In a healthy vaginal microbiome, Lactobacillus species are dominant and protective. These bacteria generate lactic acid from glycogen, a process that maintains a low vaginal pH; this acidic pH environment inhibits the growth of other bacterial species that are normally present in the vagina at very low levels.

The process of vaginal dysbiosis usually begins with the colonization of the vagina by a virulent strain of Gardnerella species, typically following sexual exposure.

The proliferation of the Gardnerella species displaces vaginal lactobacilli and creates a biofilm scaffolding. 

The biofilm scaffolding produced by Gardnerella species is conducive to recruiting Prevotella bivia (and other bacteria associated with the development of bacterial vaginosis).

Gardnerella species and Prevotella bivia engage in a synergistic relationship in which they produce sialidase, a proteolytic carboxylase enzyme, and this promotes breakdown of the mucous layer on the vaginal epithelium.

The continued production of sialidase promotes breakdown of the vaginal epithelial layer and this increases adherence of other strict anaerobes, including Fannyhesseae vaginae, Sneathia species, Megasphaera type I, and other bacteria, which add to the biofilm on the upper layers.

Fannyhesseae vaginae stimulates a strong host immune response from vaginal epithelial cells, leading to localized pro-inflammatory cytokines.

In the final phase of this transition to bacterial vaginosis, mucus degradation occurs, the vaginal pH is elevated, and multiple harmful compounds are produced (biogenic amines, toxic metabolites, and proinflammatory cytokines)—all resulting in a final state of vaginal dysbiosis, including the presence of vaginal epithelial cells covered with bacteria (clue cells).

Recurrent anogenital herpes simplex infection manifesting with two, small, shallow, tender perianal erosions (blue oval). There was no induration nor erythema.

Primary syphilis. This man developed two oval, firm, non-tender, raised ulcers on the shaft of the penis (just inferior to glans).

Psoriasis on penis. Erythematous scaling patches on the shaft and glans of the penis. 

Linear burrow on the shaft of the penis caused by scabies. The rash on the penis was intensely pruritic. This man also had papules and burrows on his hands bilaterally.

Papular, pruritic lesions on the left hand caused by scabies.

Papular, pruritic lesions and excoriation from scratching on right hand caused by scabies.

Hyperpigmented, maculopapular rash on the soles of feet in a man with secondary syphilis.

Hyperpigmented, maculopapular rash on the soles of feet (right foot shown) in a man with secondary syphilis.

Diffuse erythematous, macular rash on the left hand in a woman with secondary syphilis. 

Diffuse erythematous, Macular/papular rash on the left chest and upper breast region in a woman with secondary syphilis. 

Papular and pustular rash on right foot in a man with secondary syphilis.

Erythematous, maculopapular rash on left palm in a man with secondary syphilis. 

Erythematous, maculopapular rash on bilateral palms in a man with secondary syphilis. 

Patch of hair loss on scalp in a man with secondary syphilis. 

Man with two large verrucous plaques on the right perianal region that was confirmed as secondary syphilis and condylomata lata. A sample from one of the lesions, when viewed under Darkfield microscopy, was teeming with spirochetes).

Painful (burning sensation), erythematous, vesicular lesions that developed unilaterally in cranial nerve V1 distribution on the right forehead caused by herpes zoster (shingles).

Diffuse maculopapular rash from secondary syphilis with lateral view of the right thigh. 

Diffuse maculopapular rash from secondary syphilis on lower left back region.

Erythematous maculopapular rash on soles in a man with secondary syphilis. 

Erythematous maculopapular rash on soles in a man with secondary syphilis. 

Painless ulcer with scaling below the lower lip in a man with primary syphilis. 

Lateral ventral view of the right side of the scrotum. Examination showed a large, nontender firm, right testicular mass in a man diagnosed with right-sided testicular cancer.

Frontal view of scrotum, testes, and bilateral  inguinal region. Examination showed a large, nontender firm, right testicular mass in a man diagnosed with right-sided testicular cancer. There is also prominent inguinal adenopathy (right greater than left).

Frontal view of scrotum, testes, and right  inguinal region. Examination showed a arge, nontender firm, right testicular mass in a man diagnosed with right-sided testicular cancer. There is also prominent right inguinal adenopathy.

Erythematous, annular, macular rash with well-defined borders in suprapubic and inguinal regions that was diagnosed as tinea cruris.

Erythematous, annular, macular rash with well-defined borders in suprapubic and inguinal regions that was diagnosed as tinea cruris.

A Bartholin gland cyst is caused by increased fluid collection in the Bartholin’s glands that develops after an obstruction in the Bartholin’s duct. A Bartholin gland cyst manifests clinically as a firm, swollen, fluid-filled lump in the tissues at the lower opening of the vagina. The cyst and tissues surrounding the cyst may become erythematous and/or tender.

A Bartholin gland abscess is an infection in the Bartholin’s gland that develops after an obstruction in the Bartholin’s duct. A Bartholin gland abscess manifests clinically as a painful, tender, swollen, erythematous, lump in the tissues at the lower opening of the vagina. The abscess is considered large if it is 3 cm or larger.

Sagittal view of the female reproductive system, including external organs (vulva) and internal organs (vagina, cervix, uterus, fallopian tube, and ovary. This image also shows the urinary system (bladder and urethra) and the lower gastrointestinal tract (rectum and anus). 

Cervical os as viewed through a speculum.  The cervical os is the central opening of the cervix that connects with the vagina (external os) and with the uterus (internal os). 

Mycoplasma genitalium is a very small (0.5 and 1.5 μm in size), flask-shaped bacteria that does not have a cell wall.  This organism has a protruding terminal (narrow) organelle that contains an structures that drive the organism’s gliding motility.

Structure of Mycoplasma genitalium (intact organism). This flask-shaped bacteria is very small (0.5 and 1.5 μm in size) and does not have a cell wall. The outermost dark blue structures are adhesion complexes and the outer green area represents the cell membrane. The protruding terminal (narrow) element contains an attachment organelle that drives gliding motility.

Structure of Mycoplasma genitalium (intact organism, translucent view). This flask-shaped bacteria is very small (0.5 and 1.5 μm in size) and the protruding terminal (narrow) element contains an attachment organelle that drives gliding motility.

Structure of Mycoplasma genitalium (hemisection). This view shows the contents of the M. genitalium cytoplasm, including the DNA, soluble RNA, ribosomes, and soluble proteins. The terminal (narrow) organelle is shown, including the wheel-like structure (red), a rod (orange), and a terminal button (yellow).

This illustration shows the terminal (narrow) element of Mycoplasma genitalium. This region contains a terminal organelle that drives gliding motility. The terminal organelle includes the wheel-like structure (red), a rod (orange), and a terminal button (yellow).

In this illustration of a woman with pelvic inflammatory disease, the left fallopian tube is inflamed and edematous, causing adhesions with surrounding structure. Acute salpingitis is the term used to describe acute inflammation of the fallopian tube caused by infection.

This illustration shows a left fallopian tube (with close-up inset) following acute salpingitis. The inset shows the development of adhesions within the fallopian tube, which can result in overall narrowing of the tube. 

This illustration shows a fallopian tube following acute salpingitis where adhesions have developed within the tube can develop, leading to narrowing and scarring. 

Following acute salpingitis and resolution of fallopian tube inflammation, adhesions within the tube can develop, leading to narrowing and scarring. These scarring changes in the fallopian tube can lead to infertility via blockage of passage of ovum from the ovary to the uterus.

This illustration shows normal appearance of epididymis, testicle, and scrotal sac. The epididymis is a coiled tube Ton the back of the testicle and it functions to store and transport sperm.

This illustration shows characteristic inflammation and swelling of the left epididymis and left scrotal sac. The epididymis is a coiled tube located on the back of the testicle, and it functions to store and transport sperm.

This illustration shows a wet mount saline microscopic examination of a vaginal smear. The clue cells on the right are vaginal epithelial cells covered with abundant bacteria.

This illustration shows a Gram stain of a clinical sample in a person infected with Haemophilus ducreyi; the field shows multiple white blood cells (blue) and chains of gram-negative coccobacillary organisms (red) aligned in parallel arrays—often referred to as a “school of fish”.

This illustration of lichen sclerosus on the vulva shows smooth, flat, hypopigmented, thinning patches bilaterally, with extensive involvement on both the labia majora and labia minora.

This illustration of lichen sclerosus on the vulva shows smooth, flat, hypopigmented, thinning patches bilaterally, with extensive involvement on both the labia majora and labia minora.

This illustration of lichen sclerosus on the penis shows several white patches of thinned skin on uncircumcised penis (on the left) and circumcised penis (on the right). The foreskin has been constricted (tightened) by this process.

This illustration of lichen sclerosus on the penis shows several white patches of thinned skin on uncircumcised penis (on the left) and circumcised penis (on the right). The foreskin has been constricted (tightened) by this process.

A Bartholin gland cyst is caused by increased fluid collection in the Bartholin’s glands that develops after an obstruction in the Bartholin’s duct. A Bartholin gland cyst manifests clinically as a firm, swollen, fluid-filled lump in the tissues at the lower opening of the vagina. The cyst and tissues surrounding the cyst may become erythematous and/or tender.

A Bartholin gland abscess is an infection in the Bartholin’s gland that develops after an obstruction in the Bartholin’s duct. A Bartholin gland abscess manifests clinically as a painful, tender, swollen, erythematous, lump in the tissues at the lower opening of the vagina. The abscess is considered large if it is 3 cm or larger.

This illustration shows multiple Donovan bodies inside a large mononuclear cell as seen on a tissue crush sample from a patient with granuloma inguinale. The Donovan bodies represent multiple intracellular Klebsiella granulomatis organisms.

Sagittal view of the male reproductive system, including circumcised penis, epididymis, testicle, prostate gland, seminal vesicle, and ductus deferens. This image also shows the urinary system (bladder and urethra) and the lower gastrointestinal tract (rectum and anus). 

Frontal view of male reproductive system, including circumcised penis, epididymis, testes, spermatic cord, and tunica vaginalis.

This illustration of a young man with testicular torsion shows apparent twisting of the spermatic cord and reduced blood flow to the left testicle. The left testicle appears slighty elevated in the scrotum compared to the right testicle.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), non-tender, flesh-colored bumps in rows around the corona of the penis.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), non-tender, flesh-colored bumps in rows around the corona of the penis.

Intact enveloped monkeypox virus. This virus, which is the cause of mpox, is oval in shape and 360 nm by 270 nm by 250 nm in size. The dark purple structures are the outer surface proteins; the blue surface of the virus represents the extracellular viral envelope.

Translucent view of intact enveloped monkeypox virus. This virus, which is the cause of mpox, is is oval in shape and 360 nm by 270 nm by 250 nm in size. The dark purple structures are the outer extracellular proteins, the blue surface of the virus represents the outer viral envelope, and the orange represents the core of the virus.

Hemisection view of enveloped monkeypox virus. The dark purple structures are the outer extracellular proteins, the blue surface of the virus represents the outer viral envelope, and the orange represents the core of the virus. The white tube-like structure represents the nucleocapsid.
 

Hemisection view of enveloped monkeypox virus. 

Mature monkeypox virus without outer envelope. The green area represents the surface proteins.

Mature monkeypox virus without outer envelope. The green area represents the surface proteins and the orange area represents the viral core.

Mpox lesions typically progress through six stages shown in this illustration: macules, papules, vesicles, pustules, crusting, and healing.

Macules are the first stage of cutaneous mpox infection. The macular mpox lesions typically begin as an erythematous discoloration involving the superficial layer of the skin. These lesions are round-oval in shape and may occur as a solitary lesion or multiple lesions.

Macules are the first stage of cutaneous mpox infection. The mpox macular lesions typically begin as an erythematous discoloration involving the superficial (epidermal) layer of the skin. These lesions are round-oval in shape and may occur as a solitary lesion or multiple lesions.

Papules are the second stage of cutaneous mpox infection. The mpox papular lesions are typically slightly raised and firm.  The papular lesions are round-oval in shape and may occur as a solitary lesion or multiple lesions.

Papules are the second stage of cutaneous mpox infection. The mpox papular lesions are typically slightly raised and firm.  The papular lesions are round-oval in shape and may occur as a solitary lesion or multiple lesions.

Vesicles are the third stage of cutaneous mpox infection. The mpox vesicular lesions are initially filled with clear fluid.  The vesicular lesions are raised, round-oval in shape, and may occur as a solitary lesion or multiple lesions.

Vesicles are the third stage of cutaneous mpox infection. The mpox vesicular lesions are initially filled with clear fluid.  The vesicular lesions are raised, round-oval in shape, and may occur as a solitary lesion or multiple lesions.

Pustules are the fourth stage of cutaneous mpox infection. The mpox vesicular lesions are initially filled with clear fluid, but subsequently typically fill with pus, generating the pustular lesions.  The pustular lesions are raised, round-oval in shape, and may occur as a solitary lesion or multiple lesions.

Pustules are the fourth stage of cutaneous mpox infection. The mpox vesicular lesions are initially filled with clear fluid, but subsequently typically fill with pus, generating the pustular lesions.  The pustular lesions are raised, round-oval in shape, and may occur as a solitary lesion or multiple lesions.

Crusting (scab formation) is the fifth stage of cutaneous mpox infection. After vesicles and pustules rupture, they begin to crust or scab, typically most prominent in the center of the lesion. hese lesions may appear ulcerated.

Crusting (scab formation) is the fifth stage of cutaneous mpox infection. After vesicles and pustules rupture, they begin to crust or scab, typically most prominent in the center of the lesion. These lesions may appear ulcerated. 

Healing) is the sixth and final stage of cutaneous mpox infection. As new healthy skin begins to develop, the scab falls off, leaving a healed surface.  

Healing) is the sixth and final stage of cutaneous mpox infection. As new healthy skin begins to develop, the scab falls off, leaving healed areas on the skin surface (blue arrows). At this point, the skin lesions are no longer contagious.  

Healing) is the sixth and final stage of cutaneous mpox infection. As new healthy skin begins to develop, the scab falls off, leaving healed areas on the skin surface. At this point, the skin lesions are no longer contagious.  

With the mpox subcutaneous vaccine, 0.5 mL is administered with each dose. 

With the mpox intradermal vaccine, 0.1 mL is administered with each dose. 

Proctitis is inflammation of the rectal region (shown in red), which is the most distal 10 to 12 cm of the lower gastrointestinal tract.

Proctocolitis (gold color) indicates inflammation of the rectum and the colon. With sexually transmitted infections involving the colon, the term proctosigmoiditis is often used interchangeably with proctocolits, since the region of the colon involved is usually the sigmoid colon.

Proctosigmoiditis (gold color) indicates inflammation of the rectum and the sigmoid colon. The sigmoid colon is an S-shaped region of the lower colon that is approximately 25–40 cm in length and the rectum is approximately 10–12 cm in length. Thus, the entire length of the proctosigmoid region is 35-52 cm. With sexually transmitted infections involving the colon, the term proctocolits is often used interchangeably with proctosigmoiditis, since the region of the colon involved is usually the sigmoid colon. 

There are three stages in the life cycle of PPhthirus pubis (crab louse): eggs, nymphs, and adults. The adult female insects lay eggs (nits) that adhere to the hair-skin junction. After approximately 1 week, the eggs hatch as first-stage nymphs that look like miniature adult lice; these nymphs go through three stages of growth over a 9- to 12-day period as they develop into adult lice. The adult females lay about 30 to 300 eggs over their 3- to 4-week life span.

This illustration shows an adult 1-2 mm Phthirus pubis (pubic louse), a 6-legged, 1-2 mm, blood-sucking, wingless insect. The pubic louse is also commonly referred to as a crab louse because it resembles a miniature crab. 

This illustration shows the difference in appearance between an empty Phthirus pubis nit and live Phthirus pubis nit. Live nits are less than 1 mm in size and contain a developing nymph. They are found attached to pubic hair. The presence of live nits on pubic hair indicates active infection and confirms the diagnosis of pediculosis pubis (often referred to as pubic lice or crabs). Empty nits, when found along with live nits, represent hatched nymphs, likely recently hatched. 

Live Phthirus pubis nits are less than 1 mm in size and contain a developing nymph. They are found attached to pubic hair. The presence of live nits on pubic hair indicates active infection and confirms the diagnosis of pediculosis pubis (often referred to as pubic lice or crabs).

Empty Phthirus pubis nit.  These empty nits are found attached to pubic hair. The presence of an empty nit alone (without evidence of any live nits) may indicate inactive or extinct infection.

This illustration shows the effect of burrowing on skin created by a pregnant female Sarcoptes scabiei mite that has tunneled into the epidermis to lay eggs. Burrows on the skin can be up to 1 cm in length and on examination have a black dot at the end, which represents larvae, eggs, or feces. Inside the burrow, there are eggs and a female mite.

This illustrations shows anterior and posterior views of an adult human and common sites (red areas) of Sarcoptes scabiei infestation: hands, wrists, elbows, axillae, groin and umbilical region.

Image of an adult Sarcoptes scabiei mite. All mites have 8 legs and are members of the arachnid family.

Image of an adult male (left) and female (right) 8-legged Sarcoptes scabiei mites. The adult female is approximately 0.35-0.45 mm in length and larger than the adult male (approximately 0.2-0.25 mm in length).

Trichomonas vaginalis is a single-celled, pear-shaped flagellated anaerobic protozoan parasite that is approximately 10 by 7 micrometers in size. This organism has four anterior flagella and one flagellum embedded in an undulating membrane. After attaching to vaginal epithelial cells, the T. vaginalis can transform into a flat ameboid-like structure.

Speculum view of the cervix (left) and a close-up view of the cervix (right) in a woman with cervicitis caused by trichomoniasis showing frothy gray or yellow-green discharge and punctate hemorrhages on the cervix (often referred to as a strawberry cervix).  

Speculum view of the cervix (left) and a close-up view of the cervix (right) in a woman with cervicitis caused by trichomoniasis showing punctate hemorrhages on the cervix, which is often referred to as a strawberry cervix.  

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing heavy purulent discharge from the cervical os. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing heavy purulent discharge from the cervical os and edema of cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing light (thin) purulent discharge from the cervical os. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing thin (light) purulent discharge from the cervical os and edema of cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing friable cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in woman with cervicitis showing easy induction of bleeding from cervix after placement of a swab into the cervix.

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing heavy purulent discharge from the cervical os and friable cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in woman with cervicitis showing friable cervix and easy induction of bleeding from cervix after placement of a swab into the cervix.

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing friable cervix and edema of the cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing light (thin) discharge from the cervical os and a friable cervix. 

Speculum view of cervix (left) and close-up view of cervix (right) in a woman with cervicitis showing edema of the cervix. 

The Chlamydia trachomatis life cycle involves five key steps: (1) attachment and entry of an elementary body into the host cell; (2) transformation of athen elementary into a reticulate body; (3) replication of the reticulate bodies; (4) reorganization of many of the reticulate bodies back to elementary bodies; and (5) lysis of cells with release of mostly elementary bodies and some reticulate bodies.

Herpes simplex virus is approximately 150 to 200 nm in diameter. The image on the left represents the intact virion and image on the right shows a cross-sectional view of the viron.

Extensive, serpiginous white plaques on the penis glans and corona in a man with Reiter’s syndrome. These may also appear as erythematous patches. Circinate balanitis is usually present in conjunction with the clinical triad of arthritis, conjunctivitis, and urethritis. 

Painful, prurtitic, erythematous, with superficial layer of ulceration caused by mpox. These lesions are beginning to heal. 

Mpox pustular lesion on left hand in web space between 4^th and 5^th fingers.

Nodular, ulcerative, dome-shaped pustular lesions on the base of the penis and in the suprapubic region just above the scrotum. These lesions, which have a dark core in the center, were confirmed as mpox. The left inguinal node is mildly enlarged.

Two round papular-pustular lesions with central crater on shaft of penis in a man with mpox. 

Two round papular-pustular lesions with central crater on shaft of penis in a man with mpox. 

Large, round, erythematous, superficial ulcerated region on the lower left chin with yellow crusting in a man with impetigo. Several days prior, the affected area was a large bullae.

Two large, dark red, oval, superficial ulcerated regions (with crusting/scabbing) on the left side of the face in a man with impetigo. Several days prior, the affected areas were a large bullae.

Two large, dark red, oval, superficial ulcerated regions (with crusting/scabbing) on the left side of the face in a man with impetigo. Several days prior, the affected areas were a large bullae.

Pustular mpox lesions (with surrounding erythema) on the left thigh. 

Pustular mpox lesions (with surrounding erythema) on the back. 

Papular mpox lesions (with surrounding erythema) on the back. 

Multiple mpox lesions on the penis, including lesions in pustular stage, ulcerative, and scabbing phase. There is severe edema of the penis. 

Multiple mpox lesions on the penis, including lesions in multiple stages of progression: pustular, ulcerative, scabbing, and healing. There is severe edema of the penis. 

Single, erythemaous papule at the base of the right thumb caused by mpox infection.

Mpox pustular lesion on lower right back. 

Erythematous, round, edematous, painful lesion on the right anterior thigh caused by mpox infection. The lesion has a central region that is dark and necrotic appearing.

Multiple painful, pustular, ulcerated anal and perianal lesions caused by mpox. Two of the anal lesions have a dark center. 

Multiple painful anal and perianal vesicicular and pustular mpox lesions. 

Mpox pustule with surrounding erythema (right forearm).

Mpox pustule with surrounding erythema (right lower back region), with close up of lesion.

Mpox pustule with surrounding erythema (right anterior chest region).

Several erythematous papules on the right shoulder in a man with early-stage of mpox infection. 

Extensive plaque-like lesions on left shoulder caused by crusted scabies in a man with HIV and AIDS.

Large, verrucous mass with a superficial yellow crust on the distal shaft of the penis. Biopsy of this mass confirmed a diagnosis of Buschke-Löwenstein tumor and human papillomavirus (HPV) type 16 infection. The Buschke-Löwenstein tumor, which is also referred to as giant condyloma acuminata, is a slow-growing tumor caused by HPV that can generate significant destruction of genital tissue.

Large, caulifolwer-like mass on the distal shaft of the penis in a man with HIV. Biopsy of this mass confirmed a diagnosis of Buschke-Löwenstein tumor and human papillomavirus (HPV) type 16 infection. The Buschke-Löwenstein tumor, which is also referred to as giant condyloma acuminata, is a slow-growing tumor caused by HPV that can generate significant destruction of genital tissue.

This illustration of a young man with testicular torsion shows apparent twisting of the spermatic cord and reduced blood flow to the left testicle. The left testicle appears signifanctly elevated in the scrotum compared to the right testicle. 

Right-sided inguinal adenopathy “groove sign” as a manifestation of lymphogranuloma venereum (LGV). The groove sign is formed by a depression in enlarged inguinal lymph nodes that surround the inguinal ligament. Lymphogranuloma venereum is caused by L1, L2, or L3 serovars of Chlamydia trachomatis. 

Hyperpigmented macules on the palms in a woman with secondary syphilis.

Oral mucous patches as shown by superficial ulcerations on the tongue in a woman with secondary syphilis.

Ulcerated lesion with dark necrotic center on the face (below the left lower lip) in a man with mpox infection. 

This illustration shows normal lower gastrointestinal anatomy.

Tyson’s glands are benign modified sebaceous glands that are a normal anatomic variant. Tyson’s glands are located on the ventral surface of the penis and both sides of the frenulum.

Tinea cruris in a man with HIV manifesting as an extensive, expanding, erythematous rash with a well-demarcated border involving in the groin, suprapubic region, and lower abdomen.

Raised, flat papules on the glans of the penis caused by lichen planus.

Raised, flat papules on the glans of the penis caused by lichen planus.

Fixed-drug hyperpigmented rash on the glans of penis caused by trimethoprim-sulfamethoxazole. 

Fixed-drug ulcerated lesion rash on the tongue caused by trimethoprim-sulfamethoxazole. 

Psoriasis plaque on glans penis in a man that has recurrent psoriasis on his hands and penis.

Erythemaous, papular excoriated lesion on the left hand caused by scabies infestation.

Erythematous papular lesion on left forearm caused by mpox.

Erythematous, round, edematous, painful lesion on the right anterior thigh caused by mpox infection. The lesion has a central region that is dark and necrotic appearing.

Multiple mpox lesions, at various phases, on the penis and associated severe edema of the penis. 

Solitary, painful, oral ulcer on the hard palate of the mouth in a man with mpox. The ulcer is covered with exudate.

Pustular mpox lesions (with surrounding erythema) on the right arm. 

Vestibular papillomatosis is a normal anatomic variation characterized by multiple, small, smooth, finger-like (filiform) projections that symmetrically line the inner surface of the labia minora.

Vestibular papillomatosis is a normal anatomic variation characterized by multiple, small, smooth, finger-like (filiform) projections that symmetrically line the inner surface of the labia minora.

Main internal organs in the female reproductive system, including vagina, cervix, uterus, fallopian tubes, and ovaries.

This illustration shows a sagittal view of the abdominal cavity in a woman with Fitz-Hugh-Curtis syndrome. Fitz-Hugh-Curtis syndrome is a complication of pelvic inflammatory disease (PID) that occurs when hepatic capsular inflammation causes adhesions between the liver capsule and the anterior abdominal wall. This inset on bottom right shows a close-up view of these thin fibrous strand adhesions. These adhesions resemble violin strings as shown here (inset on top right).

This illustration shows a sagittal view of the abdominal cavity in a woman with Fitz-Hugh-Curtis syndrome. Fitz-Hugh-Curtis syndrome is a complication of pelvic inflammatory disease (PID) that occurs when hepatic capsular inflammation causes adhesions between the liver capsule and the anterior abdominal wall. 

This illustration shows a sagittal view of the abdominal cavity in a woman with Fitz-Hugh-Curtis syndrome. Fitz-Hugh-Curtis syndrome is a complication of pelvic inflammatory disease (PID) that occurs when hepatic capsular inflammation causes adhesions between the liver capsule and the anterior abdominal wall. The inset (on right) shows a close-up view of these adhesions.

Fitz-Hugh-Curtis syndrome is a complication of pelvic inflammatory disease (PID) that occurs when hepatic capsular inflammation causes adhesions between the liver capsule and the anterior abdominal wall. This illustration shows a close-up view of the thin fibrous strand adhesions (on left). These adhesions resemble violin strings as shown here (on right).

Most cases of pelvic inflammatory disease involve an infectious bacterial pathogen introduced into the vagina that ascends through the cervix and into one or both fallopian tubes.

This illustration shows how Chlamydia trachomatis introduced into the vagina can ascend though the cervix and into the fallopian tubes, which may result in pelvic inflammatory disease.  

Following an episode of pelvic inflammatory disease and acute salpingitis, there is resolution of fallopian tube inflammation, but, in some instances, residual narrowing and scarring of the tube may occur. As shown here, narrowing and scarring of the left fallopian tube has obstructed the passage of ova from the left-sided ovary to the uterus.

This illustration of a woman with pelvic inflammatory disease shows inflammation and edema of the left fallopian tube and left ovary, with adhesions between the fallopian tube and the left ovary. 

This illustration of a woman with pelvic inflammatory disease shows severe inflammation and edema of the left fallopian tube and left ovary, with extensive adhesions between the fallopian tube and the left ovary. As shown here, this process can result in the development of a tubo-ovarian abscess. Additional adhesions have developed between the left fallopian tube and surrounding structures.

Hyperpigmented macular lesions on palms in a man with secondary syphilis.

Hyperpigmented maculopapular rash on right palm in a man with secondary syphilis. 

Verrucous mass on the proximal shaft of the penis in a man with HIV. This mass was a recurrence of Buschke-Löwenstein tumor (also referred to as giant condyloma acuminata). The prior mass was located on the distal shaft of the penis and was surgically removed.

Bullous rash on right hand that has evolved with desquamation in an infant with congenital syphilis.

Pneumonia alba in an infant with congenital syphilis.

Generalized lymphadenopathy in an infant with congenital syphilis.

Hepatosplenomegaly in an infant with congenital syphilis.

Hepatomegaly (without spleen enlargement) in an infant with congenital syphilis.

Uveitis in left eye of infant with congenital syphilis.

Cataract in left eye of infant with congenital syphilis.

Cataract and uveitis in left eye of infant with congenital syphilis.

Periosteal inflammation in left leg of infant with congenital syphilis.

Periosteal inflammation in the proximal left tibia of an infant with congenital syphilis.

Inflammation of the distal metaphysis of the left femur and destruction of the medial metaphysis of the proximal left tibia in an infant with congenital syphilis.

Close up view of inflammation of the distal metaphysis of the left femur and destruction of the medial metaphysis of the proximal left tibia in an infant with congenital syphilis.

Bartholin’s glands are approximately 0.5 mm in size, oval-shaped, and located bilaterally in the lower region of the labia at the vaginal introitus. The duct of the Bartholin’s gland drains into the vaginal vestibule. These glands produce a clear mucous fluid that provides lubrication for the vagina and vulva.

Bartholin’s glands are approximately 0.5 mm in size, oval-shaped, and located bilaterally in the lower region of the labia at the vaginal introitus. The duct of the Bartholin’s gland drains into the vaginal vestibule. These glands produce a clear mucous fluid that provides lubrication for the vagina and vulva.

External reproductive system (vulva) anatomy. 

External reproductive system (vulva) anatomy. 

This illustration shows both proctitis (red color) and proctosigmoiditis (gold and red color). The sigmoid colon is an S-shaped region of the lower colon that is approximately 25–40 cm in length and the rectum is approximately 10–12 cm in length. Thus, the entire length of the proctosigmoid region is 35–52 cm. With sexually transmitted infections involving the colon, the term proctocolits is often used interchangeably with proctosigmoiditis, since the region of the colon involved is usually the sigmoid colon. 

This photomicrograph is taken of a tissue crush biopsy sample from a patient with granuloma inguinale. Note the multiple small intracellular Klebsiella granulomatis organisms within the large mononuclear cell in the center of the image. 

This photograph of a woman with chancroid shows marked left-sided inguinal adenopathy, often referred to as a bubo. In this woman, the bubo had ruptured through her overlying inguinal skin (black arrow).
Note: this image is from the Centers for Disease Control and Prevention Public Health Image Library (Dr. Greg Hammond and Susan Lindsley, 1976).

This photograph of a man with chancroid shows two soft ulcers on the scrotum (top blue arrows) and penis (lower blue arrow), in addition to right-sided tense, inguinal adenopathy (black arrow). Chancroid is caused by the bacterium Haemophilus ducreyi. Source: CDC Public Health Image Library (J Pledger, 1976).

This photograph of a man with chancroid shows shallow, soft ulcers on the penis, covered with a yellow exudate. Chancroid is caused by the bacterium Haemophilus ducreyi. 

Photograph of the upper mouth region and hard palate showing erythematous oral candidiasis in a man with HIV and advanced immunosuppression. 

Extensive oral white plaques on the pharynx and palate caused by oral pseudomembranous candidiasis in a man with HIV and advanced immunosuppression.

Oral white patches and plaques on the buccal mucosa caused by oral pseudomembranous candidiasis in a man with HIV and advanced immunosuppression.

Pearly penile papules are a normal anatomic variant that appear as small (<1 mm), flesh-colored bumps in rows around the corona of the penis.

This photograph shows the perineal region of a woman with granuloma inguinale (Donovanosis). There is a very large, erosive, beefy red ulcer. This lesion is highly vascular and bleeds easily with contact. Granuloma inguinale is a sexually transmitted infection caused by the gram-negative bacteria Klebsiella granulomatis.

Large bilateral inguinal ulcers in a woman with granuloma inguinale (Donovanosis). The ulcers have progressed with raised borders, abundant central granulation tissue, and hypopigmentation. There is also significant edema in the right vulvar region. Granuloma inguinale is a sexually transmitted infection caused by the gram-negative bacteria Klebsiella granulomatis.

Large bilateral inguinal and penile ulcers in a man with granuloma inguinale (Donovanosis). There marked formation of raised hypopigmented granulation tissue in both inguinal ulcers. There is also extensive edema of the penis. Granuloma inguinale is a sexually transmitted infection caused by the gram-negative bacteria Klebsiella granulomatis.

Large bilateral vulvar, perineal, and ulcers in a woman with granuloma inguinale (Donovanosis). The ulcers have progressed with raised borders, with abundant granulation tissue. Granuloma inguinale is a sexually transmitted infection caused by the gram-negative bacteria Klebsiella granulomatis.

This photograph is taken of a patient with congenital syphilis who developed Hutchinson’s teeth, which are characterized by teeth are widely spaced and the bite surfaces of the incisors are notched.

Large, right-sided, fluctuant, inguinal lymph node (“bubo”) caused by lymphogranuloma venereum (LGV). There is erythema on the skin overlying the swollen lymph node. Lymphogranuloma venereum is caused by C. trachomatis serovars L1, L2, or L3.

Patient with congenital syphilis with a large perforation in the midline region of the hard palate. 

This photograph shows a patient with congenital syphilis and perforation on the hard palate due to gummatous erosion of the palate. 

Rhinitis in an infant with congenital syphilis. The rhinitis (nasal discharge) is typically heavy and intractable. This manifestation is also commonly referred to as “snuffles”. 

Rhinitis in an infant with congenital syphilis. The rhinitis (nasal discharge) is typically heavy and intractable. This manifestation is also commonly referred to as “snuffles”.

Adult Phthirus pubis (pubic louse) attached to hair as viewed under a microscope. Lice are 6-legged insects and adult pubic lice are 1 to 3 mm in length. Pubic lice are commonly referred to as crab lice because of their crab-like appearance. 

Adult Phthirus pubis (pubic louse) attached to hair as viewed under a microscope. Lice are 6-legged insects and adult pubic lice are 1 to 3 mm in length. Pubic lice are commonly referred to as crab lice because of their crab-like appearance. 

Hypopigmented patches are present on the left upper back region. This rash was caused by tinea versicolor.

Hypopigmented patches are present on the left upper back region. This rash was caused by tinea versicolor.

Multiple, purple, maculo-papular lesions on the scrotum caused angiokeratomas, which are caused by benign capillary ectasias.

Multiple, purple, maculo-papular lesions on the scrotum caused angiokeratomas, which are caused by benign capillary ectasias.

The man presented with pruritic, scaling, excoriated plaques over the scrotum and upper inner thighs bilaterally. These lesions were caused by chronic scratching. The diagnosis was lichen simplex chronicus, which is also known as neurodermatitis. 

Marked left testicular and epididymal swelling and erythema caused by epididymitis.

Marked left testicular and epididymal swelling and erythema caused by epididymitis.

This photograph shows the suprapubic region of a man with pubic lice (crab lice). The adult lice appear as tan-brown, slightly transparent oval-shaped objects and the nits appear as very small, oval-round dark dots attached to hair shafts. 

This photograph shows the suprapubic region of a man with pubic lice (crab lice). The adult lice appear as tan-brown, slightly transparent oval-shaped objects (blue arrows) and the nits appear as very small, oval-round, dark dots attached to hair shafts (black arrows). 

Rhinitis in an infant with congenital syphilis. The rhinitis (nasal discharge) is typically heavy and intractable. This manifestation is also commonly referred to as “snuffles”.

Rhinitis in an infant with congenital syphilis. The rhinitis (nasal discharge) is typically heavy and intractable. This manifestation is also commonly referred to as “snuffles”.

This adult man has several manifestations of congenital syphilis, including a saddle nose deformity and Hutchinson's teeth (smaller and more widely spaced, with notches on the biting surface).