ContentsSynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyDrug Reaction DataReferencesInformation for PatientsView all Images (15)
Psoriasis - Anogenital in
See also in: Overview,Hair and Scalp,Nail and Distal Digit
Print Captions OFF
Other Resources UpToDate PubMed

Psoriasis - Anogenital in

See also in: Overview,Hair and Scalp,Nail and Distal Digit
Print Patient Handout Images (15)
Contributors: Sophia Delano MD, Belinda Tan MD, PhD, Amy Swerdlin MD, Susan Burgin MD
Other Resources UpToDate PubMed


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.


L40.0 – Psoriasis vulgaris

9014002 – Psoriasis

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

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's 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

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required

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.

Subscription Required


Subscription Required

Last Reviewed: 08/09/2017
Last Updated: 08/09/2017
Copyright © 2019 VisualDx®. All rights reserved.
Psoriasis - Anogenital in
See also in: Overview,Hair and Scalp,Nail and Distal Digit
Captions OFF Print 15 Images Filter Images
View all Images (15)
(with subscription)
Psoriasis : Nail pits, Scalp, Onycholysis, Knees
Clinical image of Psoriasis
Well-demarcated annular scaly papules and plaques with erythema on the back.
Copyright © 2019 VisualDx®. All rights reserved.