Derm Dx: Widespread salmon-colored patches

Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis characterized by reddish orange plaques with scaling that manifest follicular keratosis, palmoplantar keratoderma, and at times, erythroderma. PRP occurs equally in men and women and shows a bimodal age distribution, peaking...

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Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis characterized by reddish orange plaques with scaling that manifest follicular keratosis, palmoplantar keratoderma, and at times, erythroderma. PRP occurs equally in men and women and shows a bimodal age distribution, peaking in the first as well as the fifth to sixth decade. Familial and acquired forms of the disease have been reported.¹

Five different types of PRP have been described, based on age at onset, course, morphologic features, and prognosis; a sixth type related to human immunodeficiency virus (HIV) infection has been added recently.¹ More than 50% of PRP are best classified as type 1 adult onset.²  

Clinical aspects of PRP can be divided into 3 components: palmar-plantar hyperkeratosis, confluent pityriasis capitis, and varying sheets of erythema with fine pityriasiform scaling.³ Classic PRP typically begins with a single erythematous patch on the upper half of the body followed within a few weeks or months by extensive zones of follicular hyperkeratosis residing within an erythematous perifollicular halo.⁴ Islands of unaffected skin, one to several centimeters in diameter, further characterize this disorder. Disease of the palms and soles is characterized by well-defined orange-colored hyperkeratoses, and keratoderma of the palms and soles has been described as resembling carnauba wax.⁵ Distal yellow-brown discoloration, subungual hyperkeratosis, nail plate thickening, and splinter hemorrhages may also occur in type 1 PRP.⁶

Topical treatment of PRP is aimed primarily at moisturization, as topical steroids have limited efficacy. Narrowband ultraviolet B light may prove efficacious.⁷ A mainstay of oral therapy is retinoid medications such as acitretin and isotretinoin, which are beneficial in most cases.⁸ Refractory PRP may warrant therapeutic trial with a biologic agent.^9,10 Untreated, many cases of PRP resolve spontaneously within 3 months to 7 years of onset.³

Aroob Moin, DPM, is a podiatry-dermatology fellow at St. Luke’s Medical Center in Bethlehem, Pennsylvania.

Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College and an adjunct assistant professor of dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, Pennsylvania.

References

1. Sehgal VN, Srivastava G, Dogra S. Adult onset pityriasis rubra pilaris. Indian J Dermatol Venereol Leprol. 2008;74(4):311-321.
2. Griffths WA. Pityriasis rubra pilaris. Clin Exp Dermatol. 1980;5(1):105-112.
3. Pincus DJ. Pityriasis rubra pilaris: a clinical review. Dermatol Nurs. 2005;17(6):448-451.
4. Monroe JR. Papules and plaques from head to foot. Pityriasis rubra pilaris. JAAPA. 2012;25(9):18.
5. Dolezal JF. Pityriasis rubra pilaris. A case report and photo essay. Cutis. 1980;26(1):37-40.
6. Sonnex TS, Dawber RPR, Zachary CB, Millard PR, Griffiths AD. The nails in adult type 1 pityriasis rubra pilaris. A comparison with Sézary syndrome and psoriasis. J Am Acad Dermatol. 1986;15(5 Pt 1):956-960.
7. Vergilis-Kalner IJ, Mann DJ, Wasserman J, Petronic-Rosic V, Tsoukas MM. Pityriasis rubra pilaris sensitive to narrow band-ultraviolet B light therapy. J Drugs Dermatol. 2009;8(3):270-273.
8. Dicken CH. Treatment of classic pityriasis rubra pilaris. J Am Acad Dermatol. 1994;31(6):997-999.
9. Garcovich S, Di Giampetruzzi AR, Antonelli G, Garcovich A, Didona B. Treatment of refractory adult-onset pityriasis rubra pilaris with TNF-alpha antagonists: a case series. J Eur Acad Dermatol Venereol. 2010;24(8):881-884.
10. Walling HW, Swick BL. Pityriasis rubra pilaris responding rapidly to adalimumab. Arch Dermatol. 2009;145(1):99-101.