title: [Idiopathic light eruption].
abstract: Idiopathic polymorphous light eruptions (PLE) are photodermatites due to an as yet unidentified photosensitizing agent. Benign estival PLE is the most frequent form: the face is spared, and as soon as the patient has acquired a slight tan the eruption will no longer occur. Juvenile spring eruption affects the free border of the helix and may be regarded as a localized and mild form of estival PLE. Polymorphous light eruptions appear as lesions of the face which may resemble lupus erythematosus; photobiological exploration reproduces the lesions experimentally in 70% of the cases; immunohistochemistry studies are in favour of an immunological mechanism. Solar urticaria is a rare physical urticaria started by UVA, UVB and/or visible light: tolerance to sunlight can be induced by repeated exposures, but it does not last. Hydroa vacciniform is a rare PLE in children with leaves smallpox-like scars; photobiological exploration reproduces the lesions with high doses of UVA applied for 3 consecutive days. The remanent photosensitivity syndrome is characterized by an extreme photosensitivity which may be very disabling, preventing the patient to go outdoors; photo-allergological exploration discloses numerous positive patch-tests or photopatch-tests to various allergens, but the role played by these allergens in the occurrence of photosensitivity remains unclear. The syndrome probably results from an exogenous photosensitivity accident that has not regressed after exclusion of the presumably responsible photoallergens. Many treatments tested for these PLE seem to be effective, but they have not yet been controlled by double-blind trials.
authors.affiliation: Service de dermatologie, CHRU de Caen.
authors.forename: D
authors.initials: D
authors.lastname: Leroy
authors.forename: A
authors.initials: A
authors.lastname: Dompmartin
mesh_terms: D006801:Humans; D006837:Hydroa Vacciniforme / Q000209:etiology / Q000473:pathology; D010787:Photosensitivity Disorders / Q000145:classification / Q000209:etiology / Q000473:pathology*; D013472:Sunlight / Q000009:adverse effects; D014581:Urticaria / Q000209:etiology / Q000473:pathology
vernacular_title: Lucites idiopathiques.