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Case of the Month with Crutchfield Dermatology BY CHARLES E. CRUTCHFIELD III, MD COURSE The first lesions of pityriasis rubra pi l a r i s t o pr e s e nt t h e m s e l v e s a r e red macu les t hat may become sca ly patches, or papules that may become sca ly pla ques. T he d isea se tends to become progressively widespread and, in time, a n er y throderma may result. Ch a ra c t er i s t ica l ly, t here a re zones within the er y throderma of seeming u n a f fec t ed (" i s la nd s of sk i n"). T he sca l i n g becomes ever more ma rked a nd is ex pressed most dra matica l ly on the sca lp. Pa lms a nd soles become hyperkeratotic and have a yellow-orange cast. In addition, ostia of follicles often are seen to be widened and plugged by horny materia l. Pityriasis rubra pilaris usua lly lasts for months, sometimes years. INTEGRATION: UNIFYING CONCEPT Pityriasis rubra pilaris is a distinctive inflammatory process whose morphologic features are unique, clinically and histo- pathologically. Papules of the condition are characterized by discrete foci of para- keratosis that alternate with orthokeratosis in both vertical and horizontal directions. The granular zone is prominent and the remainder of the epidermis is psoriasiform, rete ridges of the condition being shorter and broader than those of psoriasis. A thinly scattered profusion of lymphocytes appears around dilated venules of the superficial plexus. Tissue sections of the biopsy speci- men of a horny plug within the ostium of a follicle show a dilated infundibulum filled with corneocytes that are both orthokera- totic and parakeratotic and arranged in a manner similar to that in the altered stratum corneum. THERAPY Topical corticosteroids are appropriate for localized scaly papules and plaques on the extremities, but PUVA or retinoids given systemically are necessary for treating widespread lesions. Extracorporeal photo- pheresis and cyclosporine also have been advocated for disease that is widespread. F o r m o r e i n f o r m a t i o n , c o n t a c t C h a rl e s E . C r u t chf i e l d I I I , M D , at C r u t c h f i e l d D e r m a t o l o g y o r v i s i t CrutchfieldDermatology.com. ■ A 44'YEAR'OLD MAN presents with a red, mild-moderately pruritic rash on his chest with "islands of skin" that are spared from the rash. It started about two or three months prior to his visit. He also complains that the skin on his palms looks slightly orange and feels thicker. Diagnosis: Pityriasis rubra pilaris Upon initial clinical examination, I considered SCLE, psoriasis and also psoriasiform dermatitis (although some consider pityriasis rubra pilaris to be a type of psoriasiform dermatitis). The biopsy was consistent with Pityriasis rubra pilaris. DEFINITION This condition is an inflammator y pr o c e s s i n w h ic h le s ion s pr e s ent themselves clinica lly as red macules a nd subt le sca ly papu les. T hey soon become so conf luent that there is widespread redness and scaling punc- tuated by islands of skin that ostensibly are clear. 1 8 1 8D I A G N O S T I C S