Pityriasis Rubra Pilaris

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A 4-year-old boy was brought to the hospital because of fever (temperature of 39.4°C [103°F]) and a bright, salmon-pink rash on the palms and soles that was associated with peeling (A and B). His symptoms had been present for 2 days. During that time, he also had redness of the eyes, fatigue, and anorexia.

On examination, the patient was febrile (temperature of 37.9°C [100.3°F]) but in no acute distress. He had palmoplantar keratoderma with distinct lateral borders. Red, xerotic plaques were also noted on the knees and elbows (C). All other physical examination findings were normal.

The clinical diagnosis was pityriasis rubra pilaris. This rare chronic dermatosis of unknown etiology affects males and females equally; there is no racial predominance.¹ The condition may be inherited, although most cases are sporadic and acquired. Trauma and infections have been suggested as possible triggers.

This child had circumscribed juvenile (type IV) pityriasis rubra pilaris, which occurs primarily in prepubertal children. (Other subtypes include classic adult, type I; atypical adult, type II; classic juvenile, type III; atypical juvenile, type V; and HIV-associated, type VI.²) Type IV pityriasis rubra pilaris is characterized by sharply demarcated areas of follicular hyperkeratosis and salmoncolored erythema, typically on the knees and elbows.³ Other commonly affected sites are the palmoplantar surfaces, dorsa of the hands and feet, and the face.³ Redness and scaling of the face and scalp may be the initial clinical manifestations. Dystrophic nail changes can also occur.

Pityriasis rubra pilaris most closely resembles psoriasis and seborrheic dermatitis. The differential diagnosis may also include ichthyosis, erythrokeratodermia variabilis, and cutaneous T-cell lymphoma.

In most cases, type IV pityriasis rubra pilaris can be controlled with high-potency topical corticosteroids with 40% urea and calcipotriol. Systemic retinoic acid (when age-appropriate and alternated with topical corticosteroids) has also been found to be effective in chronic type IV pityriasis rubra pilaris. Additional treatment strategies include the use of methotrexate, azathioprine, cyclosporine, topical vitamin A, topical vitamin D analogs, and oral corticosteroids. ³

This child's rash subsided after 2 weeks of treatment with topical corticosteroids.

References:

• Zeisler EP. Pityriasis rubra pilaris-familial type. Arch Derm Symph. 1923;7:195-208.

• J Bragg, Witkiewicz A, Orlow SJ, Schaffer JV. Pityriasis rubra pilaris, type IV. Dermatology Online Journal. 2005;11:14. http://dermatology.cdlib.org/ 114/NYU/NYUtexts/0517056.html. Accessed August 4, 2008.

• Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia: WB Saunders; 2007:2705.