Evaluation of the photosensitive patient.

Evaluation of photosensitivity involves the following sequential steps. A history is useful to evaluate possible exposure to know photosensitizers, characteristics of the light-induced eruption, family history, and possible involvement of other organ systems. Distribution and morphology of the cutaneous lesions should help to delineate the disorder. Phototesting is helpful in documenting decrease in the minimal erythema doses. Photopatch testing is indicated when history and physical examination suggest the possibility of photoallergic dermatitis. Other useful investigations include skin biopsy, antinuclear antibody panel, and when appropriate, plasma porphyrin.