Lettuce is an occasional cause of allergic contact dermatitis particularly in food handlers, chefs and market gardeners. It tends to cause hand dermatitis, which spreads up the forearms. Unfortunately immediate hypersensitivity to lettuce has also been reported. This includes Urticaria and life threatening anaphylaxis. The allergy seems to cross react with chicory and endives so these vegetables may need to be avoided as well. It is a form of Compositae allergy so may also cross react with other members of this large plant family.