[Does benign summer light eruption exist?].

Background: Contrary to other countries, in which a unique entity is recognized, two sub-groups of light eruption, benign summer light eruption and polymorphous light eruption, are identified in France. Benign summer light eruption was individualized with a few criteria: age at onset between 25-35 years old, female predominance, onset within 12 hours after an intensive exposure to sun, presence of lesions on areas which have not been regularly exposed to sunlight such as the upper chest, absence of lesions on the face, improvement during the summer period and negativity of the polychromatic phototest. In fact patients usually presenting with benign summer light eruption do not have all the criteria and they gradually develop a polymorphous light eruption. The aim of this study was to quantify, among the patients presenting with a light eruption, the population with three main criteria of benign summer light eruption.

Patients And Method: Eighty-seven patients presenting with a light eruption, a polymorphous light eruption or a benign summer light eruption, were selected by a dermatologist. For each patient the presence or absence of the 3 main criteria were noted: a) no lesion of the face, b) improvement of the eruption during the summer period, c) negative polychromatic phototest.

Results: Among the 87 patients, 9 of them (10 p. 100) had the three main criteria of benign summer light eruption.

Discussion: Benign summer light eruption is either rare or defined with wrong criteria. The polychromatic phototest was gradually replaced by the UVA phototest. In fact, provocation UVA phototests do not individualize benign summer light eruption from polymorphous light eruption. Individualization of the benign summer light eruption is not justified because there is a continuous spectrum of light eruptions, ranging from the benign eruption which improves during the summer period and the chronic eruption with a high photosensitivy and lesions of the face.