Allergy Resources

Lettuce Allergy

Key Allergens

Lettuce contains one allergenic protein called Lac s 1, it is a lipid transfer protein (LTP), these proteins are resistant to heat and are found in many types of plants. Patients suffering from a more severe allergy to cooked fruit may be sensitised to this group of proteins.

Lettuce also contains a contact allergen called lactucarium which can cause skin irritation. This is the white milky fluid found in the base of the stems when the plant is picked.


You may be suffering from LTP Syndrome if you have reactions to various fruits, vegetables and nuts and your reactions continue to be severe after you have discarded the peel and have cooked the food.

Cross Reactivity

Common foods involved in LTP allergy include kiwi, strawberries, sunflower seeds, walnut, apple, mulberry, banana, pea, apricot, cherry, plum, almond, peach pomegranate, raspberry, tomato, grape, celery, peanut, asparagus, cabbage, broccoli, chestnut, lemon, tangerine, orange, hazelnut, lettuce, lentils, lupin, green bean, pear, mustard, wheat and maize.

Other plants which may cause a cross reaction on contact are chicory and endives.

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