This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables. Pityriasis Rubra Pilaris. Presented by Dr. Michael H. Ebert and Dr. Zachary Felsher. C. L., aged 10 years, has had an eruption of the face, ears, eyebrows, and upper arms since about the age of 6 months, consisting of tiny hyperkeratotic papules. The onset was gradual, the number of lesions increasing over a period of a few years. There is an associated erythema, but the mother does not remember whether this was present at the start. The patient's brother, aged 9 months, has a few similar papules but no associated erythema. The father is said to have had "bumps" on the upper arms. Clinical examination has revealed numerous, closely grouped, tiny follicular hyperkeratotic papules, with an erythematous base, on the face, neck, eyebrows, and upper arms. The degree of erythema varies from time to time. Marked dermographia is present. At the age of 2 years the patient developed a marked