Atypical Juvenile Pityriasis Rubra Pilaris: A Case Report of Early Onset With Late Diagnosis

Pityriasis rubra pilaris (PRP) is a rare inflammatory papulosquamous skin disease that has six distinct types. Type 5 PRP is called atypical juvenile PRP. Here we report the case of a 17-year-old boy with insignificant past medical history presenting with a history of persistent slowly progressing very itchy skin lesions since the age of seven years. The lesions were photoaggravated. No similar cases in the family were observed and the parents were not consanguint. Skin examination revealed scaly erythematous patches, papules and plaques all over his body. There were also ichthyosiform-like scales covering the whole body. Hair, nails, and mucus membranes examinations were normal. A 4-mm punch skin biopsy was taken. The dermis revealed hyperkeratosis with checkerboard pattern of orthokeratosis and parakeratosis, the granular layer was preserved and acanthosis with thick and short rete ridges. The dermis showed mild perivascular lymphocytic infiltrates. On the basis of the above clinicopathological findings, the diagnosis of pityriasis rubra pilaris (atypical juvenile type) (type 5) was made. The patient was started on isotretinoin capsule 20 mg twice a day and placed under periodic follow-up.