What is an Onion Allergy?
An onion allergy is a type of food intolerance where individuals react to certain foods containing onions or onions in their preparation. Individuals with an onion allergy may experience any of the following reactions: hives; difficulty breathing; wheezing; shortness of breath; coughing up blood or phlegm (blood); swelling of your face, lips, tongue, throat or chest; nausea and vomiting.
The symptoms listed above are just some of the possible side effects of an onion allergy. There could be other symptoms such as dizziness, headaches, abdominal pain, diarrhea or skin rashes.
How common is it?
According to the National Institute of Allergy and Infectious Diseases (NIAID), there were over 200,000 cases reported in 2000 alone.  However, these numbers only represent those diagnosed by doctors. People often don’t seek treatment because they think it’s nothing, or they may not even realize that they’re allergic to onions.
In fact, according to the Mayo Clinic, “Onion allergies affect about 1 out of every 10 Americans.” This means that it affects approximately one person in ten.
Symptoms of an Onion Allergy?
It is very difficult to diagnose an onion allergy since many people don’t recognize the signs and symptoms. A good example of this is people that have an allergy to latex. A lot of these people don’t know because they’ve never come in contact with latex before, and never had a reaction. They may have a reaction the first time they come in contact with it, even if they’ve had latex products on their skin many times before.
This is very similar to food allergies since a lot of people don’t realize they are allergic to certain foods until they experience a reaction after eating it.
Allergy Symptoms Caused by Onions
The symptoms caused by an onion allergy are very similar to other types of food allergies. These may include skin hives, itching, swelling of the face, lips, tongue and throat.
This can also cause nausea, vomiting and diarrhea. In more severe cases, anaphylactic shock can occur. This potentially fatal condition causes a person’s airways to swell shut, and can lead to death if untreated.
Other less severe allergic reactions can include:
Swelling of the lips, eyes, tongue and throat
How do you Treat an Onion Allergy?
The only way to treat an onion allergy is to avoid foods containing onions. Be sure to read ingredient labels when shopping, and ask restaurants about the ingredients in prepared foods. Many people find that keeping antihistamines (such as Claritin or Zyrtec) nearby helps with the symptoms of an allergic reaction.
Am I Allergic to Onions?
This is a very common question, and unfortunately there is no easy answer. Some people may exhibit classic symptoms of an allergy after eating onions, such as difficulty breathing, wheezing, itchy skin or hives. Others may experience other allergic reactions. It is also possible to be allergic to onions, but not experience any symptoms at all.
If you think you may be allergic to onions, see a doctor as soon as possible. They can perform a skin or blood test to determine if you are indeed allergic to onions.
Once diagnosed with an allergy, your doctor can give you advice on how to avoid foods containing onions, and tell you about the different treatment options should an allergic reaction occur.
Sources & references used in this article:
Power, technology and the phenomenology of conventions: on being allergic to onions by SL Star – The Sociological Review, 1990 – journals.sagepub.com
Quercetin and its anti-allergic immune response by J Mlcek, T Jurikova, S Skrovankova, J Sochor – Molecules, 2016 – mdpi.com
Garlic, onions and cardiovascular risk factors. A review of the evidence from human experiments with emphasis on commercially available preparations [see … by J Kleijnen, P Knipschild… – British Journal of Clinical …, 1989 – Wiley Online Library
Anti-inflammatory effects of onions: inhibition of chemotaxis of human polymorphonuclear leukocytes by thiosulfinates and cepaenes by KT Augusti – Onions and Allied Crops; Brewster, JL, Rabinowitch …, 1990
Biological properties of onions and garlic by W Dorsch, E Schneider, T Bayer, W Breu… – International Archives of …, 1990 – karger.com
Allergic hypersensitivity to garlic and onion in children and adults by M Corzo-Martínez, N Corzo, M Villamiel – Trends in food science & …, 2007 – Elsevier