Psoriasis of early and late onset: characterization of two types of psoriasis vulgaris.

In 2,147 patients suffering from psoriasis, evaluation of the age of onset revealed two peaks, one occurring at the age of 16 years (female) or 22 years (males) and a second peak at the age of 60 years (female) or 57 years (males). Human lymphocyte antigen (HLA) tissue typing in 112 randomly assigned patients showed that HLA-Cw6, known to be at disequilibrium in psoriasis, is present in 85.3% of patients with early onset. In contrast, 14.7% patients with late onset showed this marker. Parents (father or mother) were affected in approximately half of the patients with early onset and in none belonging to the group with late onset. Furthermore, psoriasis in patients with early onset follows an irregular course and shows a strong tendency to become generalized. On the basis of clearly defined criteria (e.g., age of onset, heritability, and clinical course of disease), nonpustular psoriasis shows two distinct forms, one of which is hereditary, with early onset, and the other is sporadic and occurs in older age.