Psoriasis is a chronic inflammatory disease of the skin with a likely immunologic basis. Hyperproliferation of epidermal cells results in thickened, scaly skin. Psoriasis is commonly categorized as mild (covers less than 3% of the body), moderate (3%-10%), or severe (over 10%). Psoriasis is fairly common in childhood but rare in infancy (infantile psoriasis).
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.
Psoriasis - Anogenital in
See also in: Overview,Hair and Scalp,Nail and Distal DigitAlerts and Notices
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Synopsis
Codes
ICD10CM:
L40.0 – Psoriasis vulgaris
SNOMEDCT:
9014002 – Psoriasis
L40.0 – Psoriasis vulgaris
SNOMEDCT:
9014002 – Psoriasis
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Diagnostic Pearls
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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
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
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References
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Last Reviewed:08/07/2022
Last Updated:07/09/2023
Last Updated:07/09/2023
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Psoriasis - Anogenital in
See also in: Overview,Hair and Scalp,Nail and Distal Digit