Psoriasis - Anogenital in
There are many differing clinical patterns of psoriasis, including plaque type, guttate psoriasis (which often follows strep throat), palmar-plantar psoriasis, erythrodermic psoriasis, and pustular psoriasis. Involvement of the inguinal areas and axillae is termed inverse psoriasis.
Psoriasis can involve the nails (up to one-third of 313 children in one study) and may also be limited to the fingernails or to body areas such as the genitals, scalp, feet, or even a solitary fingertip. Psoriasis can often be seen in the diaper area and in the skin folds of very young children.
Anogenital psoriasis is rather common and usually is comparable to psoriasis found elsewhere on the body. It can be isolated to the genitalia but often is part of a more generalized affliction. In males, inverse psoriasis is found on the scrotum, perirectal skin, and inguinal folds. Penile psoriasis is found on the glans and under the foreskin.
L40.0 – Psoriasis vulgaris
9014002 – Psoriasis
Differential Diagnosis & Pitfalls
- Tinea cruris can be easily differentiated from psoriasis by the demonstration of hyphal elements on potassium hydroxide (KOH) preparation. Concurrent tinea pedis would also favor tinea cruris over psoriasis.
- Irritant contact dermatitis will present as red, inflamed plaques, sparing the innermost folds of the intertriginous areas that are relatively shielded from irritants.
- Allergic contact dermatitis has clusters of often pruritic vesicles in a geometric pattern outlining the exposed area.
- Lichen planus presents with pruritic violaceous papules with overlying white reticulated markings (Wickham striae), most often involving the wrists and ankles.
- Seborrheic dermatitis is yellowish and greasier, as opposed to the silvery, dry scale of psoriasis. Lesions are also ill-defined, unlike the well-defined plaques of psoriasis.
- Candidiasis displays brightly erythematous plaques like anogenital psoriasis but will likely also have adjacent, smaller satellite lesions.
- Lichen sclerosus presents as hypopigmented, slightly atrophic plaques with occasional petechial fissures.
- Cutaneous Crohn disease may present as erythema, firm papules, or swelling that is usually not as well demarcated as psoriasis and should be considered in the diagnosis in any patient with a history of inflammatory bowel disease. Fistulas and perianal skin tags may also be seen in cutaneous Crohn disease.
- Fixed drug eruption
- Balanitis circinata
Drug Reaction Data