The aim of our study is to identify the allergens in patients with leg ulcers who have contact dermatitis surrounding the skin of the ulcer and compare them with a control group consisting of patients with lower extremity contact dermatitis. A total of 40 patients with chronic leg ulcers (CLU) and contact dermatitis around the skin of ulcer were included in the study. As a control group, 20 patients with contact dermatitis of lower extremity without leg ulcers were included. The patient and control groups were patch tested with 37 allergens of the European Standard Series. Of the 40 patients, 31 (77·5%) had positivity to one or more allergens, and 10 (50%) of the control group patients had positivity to one or more allergens. The number of patients who had positivity to at least one allergen was significantly higher in the patient group (P < 0·05). Positivity to the balsam of Peru and benzocaine was significantly higher in the patient group than that in the control group (P < 0·05). Contact sensitisation to benzocaine and balsam of Peru was found to be associated with the presence of CLU. The efficacy of therapy in patients with leg ulcers might be increased by avoiding these allergens.