Biologic-induced urticaria due to polysorbate 80: usefulness of prick test

P>Background The first manifestations of psoriasis begin in childhood in more than one-third of patients. However, epidemiological data of juvenile psoriasis are lacking. Objectives To compare Dutch (NL group) and Singaporean (SG group) children with psoriasis with the aim of studying the characteristics of juvenile psoriasis and to highlight similarities and differences between these different ethnic groups. Methods Data were collected from 207 patients younger than 18 years diagnosed with psoriasis from Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands and the National Skin Centre, Singapore. Results A striking difference in familial distribution was found, with more Dutch children having an affected family member (73 center dot 3% vs. 13 center dot 6%). Presence of itch and triggering factors were more common among Dutch children (80% vs. 14 center dot 2% and 33 center dot 3% vs. 7 center dot 4%, respectively). However, both groups shared similar triggering factors like stress and infections. Other similarities included mean age at presentation (NL group 11 center dot 3 years; SG group 14 center dot 1 years) and gender ratio (NL group, M/F 1 : 1 center dot 1; SG group, M/F 1 : 1 center dot 4). Plaque psoriasis was the most common type in both cohorts while guttate and pustular psoriasis were rare. In both groups, the head, followed by the limbs, was the most common site involved. Similar proportions of children in both countries had nail involvement and psoriatic arthritis was rare. Conclusions The disparity in familial distribution may point to genetic differences between the two groups. Further studies to evaluate this difference in familial distribution may contribute to the understanding of the pathogenesis of psoriasis.