Allergy to lettuce isn’t a common one, but it can be serious. It can range from having an anaphylactic shock right after coming in contact with lettuce to suffering from a delayed hypersensitivity. The Allergy Lettuce test, also known as, Allergy Lettuce Enzyme Assay Skin is performed on a sample of skin to measure the level of allergic reaction in the skin. Some of the lettuce allergy symptoms are itchy and swollen lips and tongue, hives, eczema and in serious cases, anaphylactic shock.