Onions are in the Amaryllidaceae
family of plants which also includes shallots, spring onions (scallions) and leeks. Allergy to onion is very rare, but it can cause allergic contact dermatitis and urticaria.
An allergy to onions after ingestion is more commonly linked to Non-IgE mediated allergy
than a true IgE allergy. It is important if you think you are allergic to complete a food diary to ensure you are not eliminating large groups of food unnecessarily. There are tips on how to make a Food Diary
One of the allergens identified in onion are lipid transfer proteins
which are panallergens with the potential to cause allergy over large groups of seemingly unrelated foods.
The other identified allergen is a profilin protein
. Again this is a panallergen.
If you have allergic symptoms to multiple foods you may be suffering LTP Syndrome
Allergy to onion can be linked to Celery-Mugwort-Spice Syndrome
this is when people are affected by profilin proteins in multiple foods.
An allergy to onion is most often associated with contact dermatitis and urticaria (hives and wheals on the skin), this is due to diallyl disulphide.
Onion is in the Amaryllidaceae plant family, other plants in this family are chives, leeks and garlic. If your allergy is severe these plants may also cause allergic reactions.
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.
Profilin proteins are also found in celery, peanut, soyabeans, walnut, lupin, almonds, mustard, hazelnut, kiwi, pineapple, chilli, melon, orange, strawberry, lychee, apple, banana, aubergine (eggplant), peach, pear, tomato, dates, cherry, carrot, barley and wheat.
DermNet NZ - Onion
Allergen Encyclopedia - Onion
Healthline - Am I Allergic to Onions?
Anaphylaxis Campaign - Onion and Garlic Allergy
Dermnet NZ - Onion
Articles and Journals
Pru p 3 oral immunotherapy efficacy, induced immunological changes and quality of life improvement in patients with LTP syndrome, 2020
Allergic hypersensitivity to garlic and onion in children and adults, 2020
Garlic and onion sensitization among Saudi patients screened for food allergy: A hospital based study, 2013
Involvement of Lipid Transfer Protein in onion allergy, 2007
A case of onion allergy, 2001
Bronchial asthma, rhinoconjunctivitis, and contact dermatitis caused by onion, 1994
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