Photosensitivity reaction induced by erlotinib

We describe the case of a 70-year-old man with non-small-cell lung cancer who received erlotinib and developed skin eruptions. He noted erythema on his face, head, neck, a V-shaped area of his chest, and the dorsum of his hands after exposure to sunlight 12 weeks after the beginning of erlotinib treatment. The skin eruption spread only on sun-exposed areas. Histological findings showed lichenoid dermatitis with lymphocyte infiltration, and a reduced minimal erythema dose was observed. Photo patch testing revealed a positive reaction, confirming erythema to be a photosensitivity reaction to erlotinib. The photosensitivity reaction is a rare toxicity in erlotinib treatment. It is important to distinguish a photosensitivity reaction from a common skin rash due to erlotinib such as acneiform eruptions.