Sunlight and the skin.
D000328:Adult; D005260:Female; D006801:Humans; D006837:Hydroa Vacciniforme / Q000209:etiology; D008180:Lupus Erythematosus, Systemic / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010383:Pellagra / Q000209:etiology; D010787:Photosensitivity Disorders / Q000209:etiology; D011164:Porphyrias / Q000209:etiology; D012871:Skin Diseases / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D013471:Sunburn; D013472:Sunlight; D014581:Urticaria / Q000209:etiology; D014983:Xeroderma Pigmentosum / Q000209:etiology