Abstract
Photodermatoses can be divided into four general categories: immunologically mediated photodermatoses, drug- and chemical-induced photosensitivity, DNA repaired deficient photodermatoses and photoaggravated dermatoses. In this review, selected photodermomatoses will be discussed: polymorphous light eruption, chronic actinic dermatitis, solar urticaria and porphyria cutanea tarda. The frequency of photodermatoses has been reported from studies assessing patients in photodermatology referral centers in different parts of the world. All studies consistently showed that polymorphous light eruption is the most common primary photodermatosis, ranging in frequency from 23 to 65% of the patients referred to those centers for evaluation. Other commonly seen primary photodermatoses include solar urticaria and chronic actinic dermatitis. In studies reported from Singapore and Melbourne, Australia, photoaggravation of skin diseases was also seen commonly, probably owing to the high level of sun exposure experienced by patients seen at these locations.