A 52-year-old man was treated with weekly 40 mg/m2 methotrexate monotherapy as palliative treatment because of an irresectable recurrence of an oropharyngeal carcinoma. Five months before he received primary chemoradiotherapy, consisting of weekly cisplatin 40 mg/ m2 combined with radiotherapy to the tumour as well as the neck, with a maximum of 68G y, for a cT4aN2bM0 oropharyngeal carcinoma. He tolerated this therapy well, with only mild adverse events. The physical examination before starting the methotrexate revealed no abnormalities of the skin. After three doses of methotrexate a brisk and itchy erythema developed on the chin, which expanded rapidly to the whole neck (figure 1 and 2).