•The rate of skin toxicity due to concomitant use of cetuximab and RT is unknown.•A systematic review was performed to define its incidence in head and neck cancer.•Out of 2152 patients, the mean rate of severe radiation dermatitis was 32.5%.•Contributing factors to its development and limitations of our study were analyzed. Radiotherapy plus cetuximab is an effective combination therapy for locally advanced head and neck squamous cell carcinoma. The aim of our study was to determine the frequency of skin toxicity in patients receiving the combined treatment. Forty-eight studies were included in our analysis, for a total of 2152 patients. The mean rates of G3/G4 radiation dermatitis and acneiform rash were 32.5% (SD: 20.4; 95% CI: 28.5–36.5) and 13.4% (SD: 11.5; 95% CI: 11.2–15.6), respectively. The majority of studies referred to CTCAE scales for reporting both side effects (85.7% and 92.1%, respectively). Data on the management of skin toxicity were available in only 35.4% of the reviewed literature. severe radiation dermatitis is a frequent side effect induced by the combination of radiotherapy and cetuximab in head and neck cancer. The lack of predictive biomarkers of toxicity hampers the possibilty to design preventive measures on a personalized basis.