Allergic contact dermatitis occurs as a result of delayed hypersensitivity reaction caused by various exogenous substances. Here, a case of allergic contact dermatitis due to medical mask use is presented. A 39-year-old female patient was admitted to Allergy outpatient clinic with complaints of red and itchy maculopapular lesions, and small blisters on the cheeks, nasolabial folds, chin and neck under the chin that started three days ago. She had no chronic illness, massive sunshine exposure, history of systemic and topical medication intake and cosmetic use. The patient has been using washable masks for the whole COVID-19 pandemic period, however she used medical masks instead of washable ones 15 days ago once and for the last two days before the beginning of her complaints. Even though there was no reaction in her first contact, the above dermatitis lesions restricted to mask area developed 24-48 hrs after starting to use it for the second time. Allergic contact dermatitis was diagnosed due to skin lesions suitable with dermatitis and occurrence of the reaction after the second contact to a suspicious substance. She was recommended to stop using medical masks, and a treatment of oral antihistamine and topical steroid was prescribed. After her complaints resolved completely, a challenge with a different brand of medical mask was performed, and no reaction was observed. As a result, this case implicates that allergic contact dermatitis may occur due to using medical masks, and it is important to use masks with standardized approval since they are essential in preventing airborne infections including corona virus.