Onions are a common ingredient in many dishes, from salads to soups and stews. However, some people may develop an allergy to onions, which can cause mild to severe symptoms. In this article, we will discuss the possible symptoms of onion allergy, as well as other aspects of this condition.
Can You Be Allergic to Onions?
Yes, it is possible to be allergic to onions. Onion allergy occurs when the immune system mistakenly identifies the proteins found in onions as harmful, and produces an allergic reaction. Onion allergies are relatively rare, but they can cause significant discomfort and even life-threatening symptoms in some cases. This can result in a range of symptoms, from mild to severe, including itchy or watery eyes, runny nose, hives or skin rash, swelling of the lips, tongue, or throat, difficulty breathing, abdominal pain, nausea, vomiting, diarrhea, and in severe cases, anaphylaxis. Anaphylaxis is a medical emergency that requires immediate treatment with epinephrine (EpiPen) and a call to 911.
Why are you allergic to onions?
Allergies occur when the immune system reacts to a substance that it considers to be harmful, even though it is not. In the case of onion allergy, the immune system mistakenly identifies the proteins found in onions as a threat, and produces an allergic reaction. The exact reason why the immune system reacts to onions is not known, but it is thought to be related to genetic and environmental factors.
Onion allergy vs onion intolerance
Onion allergy and onion intolerance are two different conditions that can cause similar symptoms.
An onion allergy is an immune system reaction to the proteins in onions. When someone who is allergic to onions consume them, their immune system perceives these proteins as harmful and overreacts, leading to an allergic reaction. The symptoms of an onion allergy can range from mild to severe and can include skin rash, hives, runny nose, watery eyes, difficulty breathing, digestive problems, and anaphylaxis.
On the other hand, onion intolerance is a non-immune response to the carbohydrates in onions. When someone with onion intolerance consumes onions, their digestive system may not be able to break down the carbohydrates properly, leading to symptoms such as bloating, gas, abdominal pain, and diarrhea. Onion intolerance is not life-threatening, unlike onion allergy, which can cause severe reactions.
Onion Allergy Symptoms
An onion allergy occurs when the immune system overreacts to proteins found in onions, causing an allergic reaction. The symptoms of an onion allergy can range from mild to severe, and can include:
- Skin rash or hives: A skin rash or hives may appear on the body, which can be itchy, red, and swollen.
- Runny nose: The nose may become runny, congested, or stuffy.
- Watery eyes: The eyes may become watery, itchy, and red.
- Difficulty breathing: In severe cases, an onion allergy can cause difficulty breathing, shortness of breath, and wheezing.
- Digestive problems: Onions allergy can also cause digestive problems, such as abdominal pain, bloating, nausea, vomiting, and diarrhea.
- Anaphylaxis: In rare cases, Onions allergy can cause a life-threatening reaction known as anaphylaxis, which can cause swelling of the throat, difficulty breathing, a rapid pulse, and a drop in blood pressure.
Onions can induce both immediate and delayed reactions. Most cases of onion allergy involve rhino-conjunctivitis, asthma, and contact dermatitis. In rare cases, onion allergy may result in anaphylaxis. One case study identified a 35-year-old man who experienced anaphylaxis after ingesting cooked onions. Anaphylaxis was also reported in another patient after eating raw or lightly-cooked onions, with symptoms including intense itching, urticaria, confusion, blurred vision, transient loss of consciousness, sweating, and tachycardia, which means he suffered a heart rate over 100 beats a minute. It’s important to seek medical treatment as soon as possible if you experience onion allergy symptoms.
How common is Onion Allergy?
Onion allergy is relatively rare, but it can occur in both children and adults. According to a study published in the Journal of Allergy and Clinical Immunology, onion allergy accounts for less than 1% of all reported food allergies. However, it is important to be aware of the symptoms of onion allergy and to seek medical attention if you experience any of them.
Onion Allergy Diagnosis
An allergist may diagnose onion allergy in many ways, such as through a blood test or food challenge. A blood test measures the amount of onion-specific IgE antibodies in the blood, which indicates whether you are allergic to onions. This is a safe way to test for allergies but results may take a few days to come in. During this time, we recommend patients avoid onions.
In some cases, your allergist may perform an oral food challenge, which involves consuming small amounts of onion under medical supervision to observe for any allergic reactions. A physician will have emergency medical treatment on hand to treat any symptoms that may arise. This test is considered high-risk, so it’s important not to try this challenge at home.
Onion Allergy Treatment
The best treatment for onion allergy is avoidance. If you are allergic to onions, remove them from your diet immediately. You should also carefully read labels before consuming any new food product containing onions. When dining out, ask to see an allergen menu before you order. This will help prevent any allergic reactions.
For severe onion allergy cases, you should also carry an epinephrine auto-injector. Epinephrine is currently the only effective treatment for allergy-induced anaphylaxis. Your doctor can prescribe an EpiPen or Auvi-Q for emergency situations.
For less severe cases, antihistamines can treat your symptoms. Some medications are available over the counter, but you may need a prescription-strength cream or an inhaled corticosteroid. Contact the allergists at NY Allergy & Sinus Centers for personalized treatment options.
What are the foods to look for that cause allergy?
There are many different foods that can cause allergic reactions, but some of the most common ones include:
- Milk: Cow’s milk is one of the most common food allergens, especially in children.
- Eggs: Eggs are another common food allergen, especially in young children.
- Peanuts: Peanut allergies can be severe and life-threatening, and they are becoming more common.
- Tree nuts: Tree nuts such as almonds, walnuts, and cashews can also cause severe allergic reactions.
- Soy: Soy is a common ingredient in many processed foods and can cause allergic reactions in some people.
- Wheat: Wheat allergies are common, and they can cause symptoms ranging from mild to severe.
- Fish: Fish allergies are more common in adults than in children and can cause severe allergic reactions.
- Shellfish: Shellfish such as shrimp, lobster, and crab can also cause severe allergic reactions.
- Sesame: Sesame allergies are becoming more common and can cause severe reactions.
- Certain fruits and vegetables: Some people may be allergic to specific fruits and vegetables such as strawberries, tomatoes, and avocados.
Final Thoughts on “can you be allergic to onions?”
Having a true onion allergy is rare. Having a food sensitivity to onions is more common. Both conditions share certain symptoms, such as gastric distress.
People allergic to onions may also be allergic to garlic and other alliums, such as chives. If you’re allergic to onions, you may also be allergic to certain flowering plants, such as lilies.
Onion allergies vary in intensity from mild to severe. You can manage the condition by learning what vegetables or plants trigger your allergy, and carefully avoiding them.
Onion Allergy Frequently Asked Questions
Why Are People Allergic to Onion?
The main allergens characterized for onion include All c 3 (a lipid transfer protein), All c 4 (a profilin), and All c Alliin lyase.
How Is Onion Allergy Diagnosed?
An allergist can diagnose your onion allergy with an allergy test. Call the allergists at NY Allergy & Sinus Centers for a same-day diagnosis of your onions allergy or sensitivity.
What’s the difference between an onion allergy and a sensitivity?
If you’re allergic to onions, your immune system will identify onions, and possibly other alliums, as dangerous substances and release chemicals like histamine. These chemicals can cause symptoms ranging from uncomfortable to potentially life-threatening. Having an onion sensitivity (or intolerance) is a more common occurrence and is caused by an inability to process and digest specific foods, not by an immune system reaction.
Can Onion Allergy Cause Anaphylaxis?
It is rare, but there have been cases of anaphylaxis caused by an onion allergy. If you’re severely allergic to onion, you should always carry epinephrine.
How Is Onion Allergy Treated?
A food allergy doctor can treat your symptoms with medications, including antihistamines and epinephrine. However, it’s best to avoid onions if you are allergic to them.
Are There Other Foods Related to Onion That Can Cause An Allergic Reaction?
Foods related to onion that may cause an allergic reaction include edible alliums, such as garlic, chives, scallions, and shallots.