Pityriasis rubra pilaris is a rare chronic disorder that causes hyperkeratotic yellowing of the palms and soles and red follicular papules that merge to form red-orange scaling plaques and confluent areas of erythema with islands of normal skin between lesions.
The cause of pityriasis rubra pilaris is unknown.
The 2 most common forms of the disorder are
Atypical (nonclassic) forms exist in both age groups. Sunlight, HIV or another infection, minor trauma, or an autoimmune disorder may trigger a flare-up.
Diagnosis is by clinical appearance and may be supported by biopsy.
Differential diagnosis includes seborrheic dermatitis (in children) and psoriasis when disease occurs on the scalp, elbows, and knees.
Treatment is exceedingly difficult and empiric. The disorder may be ameliorated but almost never cured; classic forms of the disorder resolve slowly over 3 yr, whereas nonclassic forms persist. Scaling may be reduced with emollients or 12% lactic acid under occlusive dressing, followed by topical corticosteroids. Oral vitamin A may be effective. Oral acitretin (a retinoid) or methotrexate is an option when a patient is resistant to topical treatment. Other less common oral drugs include cyclosporine, azathioprine, and corticosteroids.
Last full review/revision November 2014 by Peter C. Schalock, MD
Content last modified December 2014