Photodermatoses, including phototoxic and photoallergic reactions (internal and external).

Photodermatoses are caused by an abnormal reaction mainly to the ultraviolet component of sunlight. Photodermatoses can be broadly classified into four groups: immunologically mediated photodermatoses, chemical- and drug-induced photosensitivity, photoaggravated dermatoses, and DNA repair-deficiency photodermatoses. In this review, we focus mainly on chemical- and drug-induced photosensitivity, namely, phototoxicity and photoallergy.