Dermatitis |
Irritant contact dermatitis (ICD) | Common F > M No previous sensitization needed | Irritation, pain, soreness, burning, stinging occurring weeks after exposure to weak irritants (soaps) and immediately after exposure to strong irritants (bleach)3,4 | Chronic ICD: ill-defined pink patch or thin plaque. May have slight scale Acute ICD: red edematous plaques, may be vesicular |
Allergic contact dermatitis | Common F > M Delayed-type hypersensitivity reaction; requires prior sensitization | Pruritic. Often history of exposure to prescription or over-the-counter medications (eg, benzocaine, topical antibiotics, and spermicides)3,5 | Red, edematous plaques, may be vesicular, on labia majora in females and penis and scrotum in males, perianal involvement in both sexes |
Lichen simplex chronicus | Common F > M Often prior history of atopy | Severe, paroxysmal pruritus, worse at bedtime3 | Pink, poorly marginated papules and plaques with epidermal thickening, hypo- or hyperpigmentation, prominent skin markings, scale on labia majora in females (Figure 39-1), scrotum in males |
Papulosquamous |
Lichen planus | Uncommon F > M Onset between ages 50 and 60. Most common noninfectious erosive condition of vulva. Almost nonexistent in circumcised men Rare association with hepatitis C | May be pruritic, burning, or painful. Possible dyspareunia or dysuria if vagina involved. Elicits rubbing, not scratching | White, lacy patches, flat-topped papules forming plaques, or glossy red vulvar erosions.3 May have loss of architecture with scarring. Annular lesions on penile shaft. May involve nongenital skin, vaginal, or oral mucosa |
Lichen sclerosus | Common F > M Prevalence between 1/300 and 1/1000.4 Bimodal peaks: childhood and later life (postmenopausal) | Pruritic. Painful if secondary ulceration/erosions present | White papules/plaques. Shiny, wrinkled cigarette-paper appearance.3 Ecchymoses and purpura are pathognomonic (Figure 39-2). Scarring or loss of architecture (Figure 39-3). Spares vagina (unlike lichen planus). Perianal involvement in females only. Phimosis in young boys |
Fungal |
Candidiasis | Common F > M. Obesity, incontinence, diabetes, immunosuppression, corticosteroid therapy, pregnancy, infected sexual partner, and antibiotics use predispose | Irritation, pruritus, and burning | Red plaques with scale and satellite pustules (Figure 39-4)3 Women may have vaginal discharge. In uncircumcised men, penis is often involved |
Tinea cruris | Common M > F | Pruritic or asymptomatic | Well-defined pink plaques with peripheral scale in inguinal folds and upper medial thighs, scrotum is spared (Figure 39-5) |
Viral |
Herpes simplex (HSV) | Common. Most common cause of genital ulcers. 80% of genital HSV caused by HSV-2.11 90% of HSV-2 carriers unaware of infection. 70% of HSV-2 infections transmitted during asymptomatic shedding3,6 | Prodrome: tingling, burning Acute onset of painful ulcers. Primary episode occurs 2-7 days after exposure | Small 1-3 mm vesicles on erythematous base (Figure 39-6). May rupture, forming shallow erosions. Most common on the genitals, perianal area, or buttocks |
Genital warts Human papillomavirus (HPV) | Common. Risk proportional to number of lifetime sexual partners, increased in immunosuppressed individuals.7 Peak age: mid teens to early 30s | Onset after sexual activity. Often asymptomatic. May cause pruritus, pain, bleeding, and burning | Pink, brown, red, black, or skin-colored papules and plaques (Figure 39-7A and B). Women may have cervical warts; men may have perianal warts7 |
Molluscum | Common. Bimodal distribution: children <15 years, young adults 15-29 years (as STI).8 Immunosuppression and atopic dermatitis predispose | Incubation period weeks to months. Lesions often asymptomatic. Secondary eczematization may cause itch and pain | Firm, smooth, umbilicated papules. May exhibit Koebner phenomenon |
Bacterial |
Erythrasma | Uncommon M > F More common in humid climates | Usually asymptomatic | Well-defined plaques in inguinal folds and upper medial thigh. Coral red color with Wood's light (Figure 39-8A and B) |
Hidradenitis suppurativa | Uncommon F > M. Prevalence is 1%. Obesity is risk factor. Onset after puberty | Chronic painful and tender lesions which only partially respond to antibiotics9 | Red cysts and nodules in inguinal, perianal, and genital areas. Axilla and inframammary areas may also be involved (Figures 15-11 and 15-12) |
Perianal streptococcal disease | Uncommon Children > adults. Incidence unknown | Persistent perianal itch or pain. May have pain with defecation. Satellite pustules may indicate staphylococcal infection | Sharply demarcated perianal erythema (Figure 39-9), may have fissures, characteristic foul odor.10 May involve vulva, scrotum, and penis |
Syphilis | Uncommon M > F Incidence in the United States increasing. Most new cases in men who have sex with men, ages 15-40 years11 | Primary ulcer: 3 weeks after exposure Secondary: 2-10 weeks after primary ulcer Tertiary: 3-10 years after primary Primary and secondary lesions resolve without treatment | Primary: painless ulcer (chancre) appears within 3 weeks of transmission, usually single, often glans penis in males, vulva (Figure 39-10) or cervix in females Secondary: condylomata lata (soft pink papules and nodules in perineum) |
Precancerous tumors and cancer |
HPV-related squamous cell carcinoma in situ | Uncommon F > M Younger patients with history of genital warts | Indolent asymptomatic course. Less likely to be invasive | Multifocal red, brown, or skin-colored papules or plaques on penis or perianal area in males and females and in vestibule, labia majora, and perivulvar area in females7 |
Non-HPV related squamous cell carcinoma in situ | Uncommon F > M Older patients. May have history of lichen sclerosis/planus | May be pruritic | Unifocal red, white, or skin-colored papules typically on penis, and perianal area in males and vestibule and labia minora in females (Figure 39-11A and B) |
Invasive squamous cell carcinoma | Uncommon F > M Peak age of onset is 60-70 years. May have history of genital warts or lichen sclerosus/planus3,12 | May be tender or pruritic | May present as an ulcer, plaque or exophytic nodule (Figure 39-12) typically on the labia minora or majora or clitoris in females13 and on the penis in males |
Melanoma | Uncommon M > F Rare <1% of all melanomas. May be amelanotic14 | Usually asymptomatic | Tan to black papule or plaque with asymmetry, irregular color, and indistinct borders. May be ulcerated |
Extramammary Paget's disease | Uncommon F > M Onset after 50 years of age. 15-30% are associated with malignancy15 | Asymptomatic, indolent | Well-demarcated pink scaly plaque with white epithelium on vulva or perineum (Figure 39-13) |