Complicating mucosal reactions in patients receiving radiation therapy for head and neck cancer.

Radiation mucositis is characterized by erythema, pseudomembranes, and ulceration of mucosa in the irradiated field. We present two cases of oral mucosal changes in patients treated with radiotherapy in the head and neck region, which included mucosal erythema and ulceration outside of the radiated fields. One case was confirmed as herpes virus infection, and the other was diagnosed as Sweet's syndrome. When mucositis extends beyond the radiation fields, the clinician should consider other causes of mucosal inflammation and erythema in order to begin appropriate management.