Erythema multiforme provoked by radiotherapy.

Radiation dermatitis is one of the most common adverse effects that occur in patients treated with radiation therapy. It is usually limited to the irradiated area. However, cases of generalized lesions have also been described in the literature. A rare but highly important cutaneous manifestation can be erythema multiforme-like lesions localized all over the patient's skin. A 63-year-old patient was admitted to the Department of Dermatology for disseminated erythematous lesions localized on the trunk and extremities. The patient denied taking any new medications or dietary supplements. However, he was undergoing radiotherapy treatment. On admission, the patient was in good general condition. During the stay in the department, the patient was treated orally as well as intravenously with corticosteroids, acyclovir, and a topical ointment consisting of gentamicin and betamethasone, as well as hydrocortisone and cooling ointment. After 1 month, a significant improvement in the patient's skin condition was noted. When skin lesions resembling erythema multiforme occur in patients undergoing oncological treatment, radiation therapy should be considered as a potential trigger.