Asymptomatic hyperpigmentation without preceding inflammation as a clinical feature of citrus fruits-induced phytophotodermatitis

Phytophotodermatitis is a condition that occurs by contact with plants containing phototoxic agents such as furocoumarins and psoralens with subsequent ultraviolet exposure. Phytophotodermatitis typically presents as sharply defined erythematous patches with occasional blistering, sometimes accompanied with pain or itching sensation. In some cases, however, sudden appearance of asymptomatic hyperpigmentation can be the only clinical finding of phytophotodermatitis. Here, we present two patients with sudden development of asymptomatic pigmentation on their hand without preceding inflammation by the contact with citrus fruits containing photosensitizers and subsequent exposure to strong sunlight. As like these patients, phytophotodermatitis can present with only pigmentation without noticeable inflammation especially in dark skinned people. In such cases, physician can sometimes have difficulty in diagnosis of phytophotodermatitis. Therefore, it is important to consider the possibility of phytophotodermatitis through careful history taking, especially in patients who have abruptly developed well-defined hyperpigmentation on sun-exposed areas, to avoid unnecessary test and treatment.