Flagellate skin lesions occur in some patients after eating the mushroom Lentinus edodes, and they are called shiitake dermatitis in Japan. We describe a 44-year-old man with such skin lesions on his trunk after eating L. edodes, who developed as well photosensitive skin lesions on exposed areas. Skin phototesting with UVB did not show a decreased minimum erythema dose; UVA irradiation provoked an erythematous lesion with nonspecific histological changes. Analysis of the case histories of 94 Japanese patients with shiitake dermatitis revealed that 44 (47%) also developed dermatitis on the skin exposed to sunlight. UVA photodermatitis has not been emphasized in previous reports. The relationship to bleomycin flagellate dermatitis is discussed.