Key Allergens

Lettuce is in the Asteraceae family of plants, other plants in this family include sunflower seeds, tarragon, artichoke and camomile.

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. People 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.

Food Intolerances

Food is low in FODMAP Food is moderate in sulphites Food is moderate in salicylates

Lettuce is a low FODMAP food. FODMAP stands for Fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Foods high in FODMAPs can cause symptoms of food intolerance, affecting the gastro intestinal system and this can be mistaken for a true IgE food allergy.

Lettuce is one of the few fresh foods that contains a moderate amount of sulphites. Sulphites are inorganic salts used in preservations and have the potential to cause symptoms of food intolerance to those sensitive to sulphites, this food intolerance is more common in asthmatics. An improvement in symptoms can be made with a change to a low sulphite diet.

Most lettuce varieties have a moderate amount of salicylates (iceburg lettuce are low in salicylates). salicylates have the potential to cause worsening of asthma, swelling, itching and hives as well as food intolerance symptoms in people who are sensitive to salicylates.

You can read more about Food Intolerances on the dedicated Food Intolerance Page.

Associated Syndromes

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.

Lettuce is also commonly linked to allergic contact dermatitis.

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.



Allergen Encyclopedia - Lettuce

Lipid Transfer Proteins (LTP Syndrome)

Dermnet NZ - Lettuce Contact Allergens

Anaphylaxis Campaign - Vegetable Allergies

Allergy information for: Lettuce (Lactuca sativa (Garden lettuce))

Healthline - FODMAP Foods

ATP Science - Salicylate Food List

Articles and Journals

The Association Between a Mediterranean Diet and Symptoms of Irritable Bowel Syndrome, 2024

Improving In Vitro Detection of Sensitization to Lipid Transfer Proteins: A New Molecular Multiplex IgE Assay, 2023

A case of eosinophilic pneumonia induced by lettuce, 2023

Lipid transfer protein allergy: A review of current controversies, 2022

The diagnosis and management of allergic reactions in patients sensitized to non-specific lipid transfer proteins, 2021

Asteraceae species as potential environmental factors of allergy, 2018

Lettuce Allergy and Hand Eczema, 2020

Occupational respiratory allergy to lettuce in lettuce farmers, 2020

Lipid Transfer Protein allergy in the United Kingdom: Characterization and comparison with a matched Italian cohort, 2019

Lettuce Allergy Is a Lipid Transfer Syndrome-Related Food Allergy With a High Risk of Severe Reactions, 2017

Lettuce contact allergy, 2016

Anaphylaxis to plant-foods and pollen allergens in patients with lipid transfer protein syndrome, 2013

Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen, 2003

Let me know if you found any of these interesting or useful. If you spot an article or research that you think is interesting you can message me or tag me on Facebook or Twitter - links at the bottom of the page.

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