Clinical characterisation at onset of childhood psoriasis - a cross sectional study in Sweden.

Epidemiological data in childhood psoriasis are accumulating. However, reliable information captured at onset is lacking. In a cross sectional study we recruited 109 children < 16 years within 12 months of psoriasis onset and explored the clinical characteristics. Pre-pubertal children, especially boys, more often had inverse involvement (OR = 2.8, 95% CI = 1.1, 7.1, p ≤ 0.05). HLA-C*06 was positively associated with facial lesions (OR = 3.8, 95% CI = 1.5, 9.7, p < 0.01) and guttate phenotype and was more common in pubertal children. A high PASI score was not associated with overweight or early age at onset, and gender did not influence disease onset. Psoriasis can be difficult to diagnose in children, especially in pre-pubertals. Thorough examination of facial and genital areas can help in establishing the diagnosis. Our published genetic data in combination with the clinical findings presented herein indicate that puberty may separate different populations of childhood psoriasis.