Case of photodermatitis caused by Mytilus edulis (blue mussel) presenting with edematous erythema

Animal-induced photodermatitis is rare, here we report an unusual case of photodermatitis caused by Mytilus edulis to arouse the attention of dermatologists and the education to the public. Clinically, exogenous photosensitizing dermatitis (EPD) includes photocontact dermatitis and actinic drug eruption, and the former can be divided into phototoxic contact dermatitis and photoallergic contact dermatitis. Phytophotodermatitis is a common skin lesion mainly caused by acute phototoxic inflammatory reactions. However, animal-induced photodermatitis is rare, and cases of bullacto-photodermatitis have been reported in China, but its pathogenesis is still unclear. Here we report an unusual case of photodermatitis caused by Mytilus edulis (blue mussel) with edematous erythema as the main manifestation.