Photodermatoses: classification, evaluation and management

Photodermatoses are skin disorders induced or exacerbated by light. They can be broadly classified into four groups: (i) immunologically mediated photodermatoses (idioapathic); (ii) drug- and chemical-induced photosensitivity; (iii) defective DNA repair disorders; and (iv) photoaggravated dermatoses. The exact pathomechanism of those diverse skin reactions to light radiation remains unclear. Immunologically mediated photodermatoses are the most common dermatoses among all photosesnsitive disorders. The management of photodermatoses starts with clinical recognition of characteristic lesions localized predominantly in light exposed skin. Detailed history-taking, phototesting and photopatch testing are required to establish a correct diagnosis, especially if patients present in disease-free intervals. Classification and short description of distinctive clinical features of most common photodermatoses, several practical aspects of evaluation and management of the patient with photosensitivity will be outlined.