Childhood-onset pityriasis rubra pilaris with immunologic abnormalities

We examined a 6-year-old boy with seborrheic dermatitis like redness of the face, scaling of the scalp, and palmoplantar keratoderma. Skin biopsy showed hyperkeratosis, parakeratosis, follicular plugging, and mild upper dermal perifollicular mononuclear inflammatory infiltrate, which are compatible with the diagnosis of pityriasis rubra pilaris. Immunologic studies revealed normal values of peripheral B and T lymphocytes. The spontaneous activity of T suppressor cells was activated and the function of T helper cells was impaired, however.