Pityriasis Rubra Pilaris

Pityriasis rubra pilaris (PRP) is a group of rare skin conditions which may affect any area of the body. Generally, the condition consists of clearly defined patches of orange-red scaling on the skin. In most cases, widespread involvement, sometimes of the entire skin surface, occurs. There are several subtypes of the condition.

Classical adult onset PRP is the most common subtype, affects the head, neck and upper torso, and typically resolves spontaneously within 3 years, usually without relapse. Atypical adult onset PRP is rare, and may continue in affected persons for decades. This is usually accompanied by eczema of some type. Classical juvenile onset PRP typically develops between 5 and 10, and follows an infection in most cases. This type of PRP usually resolves within 1 year. Circumscribed juvenile PRP is fairly common, presenting prior to puberty and is typically localized to the palms, soles, elbows and knees. Atypical juvenile onset PRP is rare, and may be inherited. It typically presents at birth or infancy, is extremely resistant to resolution and may be accompanied by ichtyosis. HIV-associated PRP is similar to classical adult onset PRP, but is more resistant to treatment.

While PRP may be associated with certain other disorders, the exact cause of the condition is unknown. Some forms of the condition may also be genetic.

Differential Diagnosis (Other conditions with similar appearance)
Cutaneous T-cell lymphoma
Erythroderma
Erythrokeratodermia Variabilis
Psoriasis, Plaque

PRP is typically diagnosed based on the characteristic appearance of the affected area. A skin biopsy will be performed to confirm the diagnosis and to rule out similar appearing conditions.