Photodermatoses in a Singapore skin referral centre

Summary The inducing or exacerbating effect of sunlight on skin diseases is often not appreciated in tropical countries, perhaps because of the perennial presence of sunlight, and a retrospective review of photodermatoses seen in a referral skin clinic was therefore carried out. The photodermatoses seen were secondary photoaggravation of primary skin diseases (32·2%), systemic drug photo-sensitivity (11·3%), polymorphic tight eruption (13%), chronic actinic dermatitis (5·3%), solar urticaria (5·3%), actinic prurigo (4%), photoallergic contact dermatitis (2·6%), porphyria (1·3%) and xeroderma pigmentosum (1·3%). Compared with the results of Western studies, there were more photoaggravated underlying skin diseases and systemic drug photosensitivity, and fewer idiopathic photodermatoses and photoallergic contact dermatitis; the common photoallergens were chlorpromazine, promethazine and musk ambrette, very similar to those seen in the West.