Juvenile pityriasis rubra pilaris
Juvenile pityriasis rubra pilaris (PRP) is a chronic disorder of cornification with onset in early childhood. PRP is usually acquired, but there are heritable forms. It can present in 3 forms: type III (classic), type IV (circumscribed), and type V (atypical).
In type III (10% of all cases), there is a fairly rapid onset of extensive, confluent, scaling plaques in association with thick keratoderma of the hands and feet. This often begins on the scalp and spreads to the trunk and extremities. Type IV (25% of all cases) is usually limited to the knees, elbows, and palmoplantar surfaces. It is the most common pediatric subtype. Type V (5% of all cases) is present from birth or in the first few years of life. It may be inherited in an autosomal dominant pattern due to activating mutations in CARD14. Overlap between these subtypes is common in children.
For more information, see OMIM.
L44.0 – Pityriasis rubra pilaris
238620000 – Classical juvenile pityriasis rubra pilaris
- Psoriasis has a more adherent scale, and larger lesions do not have areas of normal skin within them.
- Keratosis pilaris is usually limited to the extensor extremities.
- Erythrokeratodermia variabilis
- Drug eruption
- Atopic dermatitis
- Contact dermatitis (irritant or allergic)
- Sézary syndrome (rare in children; see cutaneous T-cell lymphoma)
- Type V can be confused with lamellar ichthyosis. Scleroderma-like changes of hands and feet may be observed.
- Caspase recruitment domain family member 14 gene (CARD14)-associated papulosquamous eruption refers to a distinctive phenotype with overlapping features of psoriasis and PRP. The patients typically present early in life and report a family history of psoriasis or PRP. The cheeks, chin, and ears are typically affected. This disease is difficult to treat using conventional therapies, while treatment with ustekinumab appears to be effective.