Scratch-chamber tests in food handler dermatitis.

Foods were tested by the scratch-chamber and open application techniques in 80 hand dermatitis patients, 55 of whom were food handlers. Both immediate and delayed reactions were seen. Most immediate scratch-chamber test reactions were provoked by vegetables and spices in patients with birch pollen allergy, and most delayed reactions from spices in patients with allergy to balsam of Peru, and from onion and leek. The evaluation of allergic and irritant reactions was difficult. Positive open application tests were seen in about 75% of patients with immediate or delayed scratch-chamber reactions. Immediate reactions from vegetables, fish and meat, and delayed reactions from orange and lemon peel and onion showed the best clinical relevance. Wet work, surface active agents and other irritant factors were considered the main causes, and food allergies as contributory factors only in food handler hand dermatitis.