Too Allergic

Onion allergy, garlic allergy, or Intolerance? This sure helps!

Reading time for this article is 13 mins

Onion allergy and garlic allergy are becoming more frequently diagnosed form of allergy, though the percentage number of affected people is still little, the number is increasing year after year around the world! For many people, being allergic to onion would usually mean being allergic to garlic too, and that because these two aromatic vegetables belong to the same allium family of vegetables.

This article will tend to cover the most essential aspects of dealing with onion and garlic allergy!

Contents hide

1 Onion allergy or Onion intolerance – which is it?

2 Difference between food allergy and food intolerance

3 Onion allergy – what is it?

4 What happens when allergic people consume onion?

5 How can you be allergic to onions?

6 What are the symptoms of onion allergy?

7 How severe is onion allergy?

8 Treatment for onion allergy

9 How to avoid an onion allergy reaction

10 What is onion intolerance or sensitivity?

11 Symptoms of Onion Intolerance

12 Treatment for onion intolerance

13 Testing for onion allergy and intolerance

14 Can onions cause migraines or headaches?

15 Can onion intolerance develop into an onion allergy?

16 Allergic To Garlic

16.1 Anaphylactic Reactions and Garlic Allergies

16.2 Cause, Effect, and Medication of Garlic Allergy

17 Garlic Allergy – Symptoms and Cure

17.1 Symptoms of Garlic Allergy

17.2 Treatment for Garlic Allergy

17.3 Summary:

17.3.1 Facebook Comments

Onion allergy or Onion intolerance – which is it?

There is a thin line between being allergic to onion and having an onion intolerance, though, misinterpretation between these two happens quite often. Having an onion allergy can be life-threatening to some while being intolerant to it would cause discomfort within the digestive system, and it’s rarely fatal.

Difference between food allergy and food intolerance

According to the National Health Service of England, having a food allergy will cause your immune system to trigger an attack once it comes in contact with the smallest trace amount of the food allergen. And mistakenly treat the said food proteins as an invasive “treat,” which is further displayed in the form of rashes, wheezing, itching, and other life-threatening symptoms, almost immediately after coming in contact with the allergen.

Whereas having a food intolerance is rarely life-threatening, and symptoms gradually show up after a few hours of consuming a substantial amount of the said food. Food intolerance doesn’t trigger an attack by the body’s immune system, as it mostly involves a trigger reaction within the digestive system.

Onion allergy – what is it?

Onion allergy is a condition in which after consumption of onions, the body starts reacting in an unwanted manner. Similar to all other allergies, this allergy is also triggered when allergic people consume the stimulant (onion). About 3% of the US population is allergic to onions. In most cases, onion allergic people are also allergic to garlic and other vegetables in the allium family. Studies have indicated that raw onions cause more allergy than cooked ones.

What happens when allergic people consume onion?

Onion contains many proteins. These proteins react with the IgE antibodies present in our body and trigger the mast cells. These mast cells are mainly present in the skin, pharynx, and gut. Upon reaction with the proteins, these mast cells release histamine, which causes adverse reactions in the body. Therefore it can be concluded that the primary cause of onion allergy is histamine.

While being allergic to peanuts is something that several people have heard of, being allergic to onion is not as common. Others suffer from an onion allergy, and this can have the same impact on their health as somebody that suffers from the peanut allergy reaction. 

The difference with this particular allergy is that it does tend to be something that very few people know about, so what actually happens and how severe can this reaction potentially be?

How can you be allergic to onions?

A person may prove to be allergic to either raw onions or cooked onions. Still, it is more common for a person to display a more allergic reaction to raw onions, and it is often due to them reacting to what, for most people, are harmless proteins contained in the vegetable. 

The body produces antibodies medically referred to as IgE antibodies, and they then react against the proteins in the onion, leading to the body producing excessive amounts of histamine from the gut, pharynx, and even the skin. 

The problem with too much histamine is that your body then has an adverse reaction to this, and it is this reaction that shows up as an allergic reaction.

What are the symptoms of onion allergy?

Onions allergy symptoms – What are the symptoms of this type of allergy?

Onion allergy is a type of contact allergy. 

The symptoms of onion allergy are very much similar to other allergies. The symptoms may appear at different times after the consumption of onions. There is a considerable gap in the timeframe, and a person may experience the signs immediately after its consumption or within a few hours.

A person who is suspected of being allergic to onion would display symptoms quite common to dermatitis, as it tends to affect the skin (or the digestive tract)more than anywhere else on the body. 

The most common symptoms of onion allergy include: 

  • feeling itchy all over your body
  • the appearance of hives
  • nausea
  • diarrhea
  • being bloated
  • excess gas

It is important to note that developing a severe reaction to onions, also known as an acute reaction or a true onion allergy is very rare.

Symptoms of true onion allergy include: 

  • changes to your breathing
  • Blood pressure drop
  • Feeling very dizzy 
  • Being in a state of confusion
  • And ultimately shock, which is also called anaphylaxis shock.

The time an individual will take to react to an exposure to onions vary from one individual to another. This is mainly affected by the strength of an individual’s immune system to the allergen and the amount of onions eaten or inhaled. 

Some individuals will react in just a few minutes after an onion exposure, while others will be able to take a much longer time of up to two hours before showing symptoms of exposure to the allergen.

How severe is onion allergy?

Onion allergy symptoms can range from mild to fatal. An onion allergy is, in most instances, relatively mild, and it will not cause you any long-term health problems. 

Most symptoms of onion allergy are treatable using simple over-the-counter antihistamines. Only a small percentage of allergy individuals will need to carry an EpiPen, and most people will only have some mild discomfort that will pass in the shortest possible time.

Treatment for onion allergy

There is no permanent treatment for most allergies, which also includes onion allergies. Treatment for most allergies involves managing the symptoms caused due to the allergic reaction.

It has been rightly said that prevention is better than cure. Therefore the best treatment is to avoid the consumption of onions. 

An onion allergic person must be overcautious about what he eats because onion is an integral part of many recipes, and sometimes though it is not used directly, its derivatives may be present. People with such allergy must go through the list of ingredients present on the packets of each processed food and also take special care when eating outside.

However, treating the allergic reaction from onion is a straightforward process because, in most instances, antihistamines will manage to clear up the allergy in a short time. 

These tablets are, of course, available over the counter, so there will be no need to contact your doctor for a prescription unless the reaction that you tend to have is more severe. 

If you develop hives, then applying atopical ointments on the affected areas will, in most cases, clear it up. Alternatively, your doctor may decide to prescribe some corticosteroids, which will also clear up more severe external symptoms.

If you at risk of suffering from anaphylactic shock, then you will be given a shot of epinephrine. This self-injection shot is effective in reducing the severity of the reaction as soon as it’s administered. Epipen is the same life-saving “treatment,” which peanut allergy sufferers are given, and there is no doubt that it has saved countless lives over the years.

How to avoid an onion allergy reaction

Onion does appear in so many items, including its use as a food preservative, and it does, of course, mean that you need to spend time reading the ingredient labelings of every product, carefully, before you eat anything. One point that should be mentioned is that quite often, people are only allergic to the raw onion and its composing ingredients, and they are usually okay when it is cooked. It may be worthwhile trying them and see how you feel after doing so. 

Apart from that, it comes down to common sense and paying attention, and you should be able to reduce the chances of having any kind of reaction.

What is onion intolerance or sensitivity?

Are you onion intolerant or sensitive? What is onion intolerance, also called onion sensitivity

Intolerance or sensitivity to food is a mild reaction to some or all of the compounds in it. This is often confused with allergy, as the symptoms may be similar. 

The significant difference between the two is that allergies attack the immune system and affect many organs. Intolerance, on the other hand, is limited to the digestive tract. 

Onion intolerance is described as mild reactions to food containing onions often characterized by the inability to digest them. 

This condition usually goes unnoticed by some victims who don’t experience all of the symptoms of intolerance to onions. Many just suffer bad breath after consuming onions. It goes away soon after brushing, so they don’t pay much attention to it. 

According to extensive studies, a type of protein present in onions reacts with various antibodies to trigger excessive production of histamine, which goes on to inhibit bodily functions like digestion. 

The lack of vital enzymes for digestion of onion proteins also leads to the following signs of onion intolerance.

 French onion soup is definitely off-limits if you’re onion intolerant.

Symptoms of Onion Intolerance

As previously mentioned above, reaction to onion intolerance is displayed within the digestive system. The sufferer may exhibit signs of discomfort when around onions, either in its cooked or raw state, this may be followed by nausea. 

This reaction is as a result of sulfur in the onion that might smell foul to some. Hives and sores on the mouth are a common sign of onion intolerance. 

These symptoms last about a month, and patients are very uncomfortable. He/she has to deal with itching all over the body, which later leads to irritability. 

Bloating is also a common occurrence among those who suffer this condition, and it is mostly coupled with stomach cramping.

Treatment for onion intolerance

The easiest way to curb onion intolerance is to stay away from them for some time. It helps with the symptoms, and once they have disappeared, you may choose to eat them again to see if the intolerance is gone. Experts at food intolerance guide their patients with intolerance to raw onions to start cooking them. However, most people are allergic to cooked and raw onions alike, prompting physicians to employ more decisive tactics.

As stated before, onions trigger the production of histamine, so a treatment program will involve the intake of antihistamines to reduce swelling. For the skin, hydrocortisone is administered. In cases of extreme intolerance (allergy), injections of epinephrine are recommended. If you witness intolerance onions, it is best if you see a doctor so they can determine whether you bear symptoms of intolerance or otherwise. This is because when intolerance is left without treatment, the patient may suffer severe allergic attacks in the future. Likely, people with this condition cannot tolerate onion related foods like kale, garlic, and chives. It is safe to steer clear of processed or canned foods as they contain onions in various forms.

Testing for onion allergy and intolerance

In many cases, a person may not be allergic but is intolerant to onions. Such a person may suffer from some small problems when onion or garlic is being cooked. These are problems like burping, burning sensations in the mouth, blisters in mouth, gums, or throat. These people have difficulty in digesting onions. Therefore it is a necessity to identify whether the person is intolerant or allergic to onions. You can identify your intolerance by blood tests and allergy tests.

Can onions cause migraines or headaches?

People with intolerance of onions or allergies are prone to migraines and may lose focus at times. Although there hasn’t been a conclusive finding of the cause, research shows that the culprit for the headaches/migraines is due to the presence of tyramine in onion and other allium vegetables.

Thereby causing the release of histamine that inhibits normal bodily functions. 

Can onion intolerance develop into an onion allergy?

Although some victims of onion intolerance may experience swelling on the face as well as skin reactions, which is quite similar to an allergic reaction, intolerance reaction to onions can not develop into an allergic reaction. 

Allergic To Garlic

When the body identifies harmful proteins in the food we eat, we usually suffer from food allergies. Once identification has been made, the immune system tries to fight the allergies. However, garlic allergies are quite uncommon but occur more often in chefs who deal with garlic regularly in their professions.

However, what you should understand is that allergies don’t manifest themselves only when you consume food with the allergens; it is also common when you breathe in the particles or even handle it on your hands. But how do I know that I am suffering from garlic allergy? Well, the symptoms of the condition vary a lot. Some might be subjected to specific symptoms, while others might not.

However, the most common symptoms of garlic allergy include:

  • Several skin reactions, redness, swelling, hives, and eczema
  • Swelling and itching of the lips, tongue, and mouth
  • Respiratory system complications like difficulty in breathing, wheezing, stuffy nose and sneezing
  • Symptoms in the gastrointestinal area like nausea, vomiting, abdominal pains and diarrhea
  • Blood pressure drops, lightheadedness, and fainting. Mostly referred to as cardiovascular symptoms.

Anaphylactic Reactions and Garlic Allergies

The above symptoms are known to be associated with garlic allergy and are mainly referred to as anaphylaxis reactions. It is advised that You seek immediate medical attention as the condition can be fatal. 

However, with a severe anaphylactic reaction that has further proven to cause dizziness, unconsciousness, confusion, and a rapid rise in the pulse rate, you are advised to do one thing. The only safety assurance would be to carry epinephrine, also called an Epipen, to treat yourself whenever you come across any form of garlic. 

Other treatment measures would include exposing the affected part in Ultra Violet rays (also known as PUVA Therapy) and the application of the psoralen drug.

Cause, Effect, and Medication of Garlic Allergy

As stated earlier, garlic allergy is a condition resulting in inflammation of the skin when you come in contact with garlic oil, garlic dust, or garlic bulb, either by consumption, inhalation, or direct contact. 

It is also prevalent for people who are associated with regular cooking. The effects of the allergy present themselves in the tips and especially middle, thumb, and index fingers of the non-dominant hand. The effects are quite severe and might lead to excess finger complications, such as an asymmetrical pattern of the fissure in the fingers.

These further proceed to the shedding of the outer layers of the fingers due to thickening. The final stage of the fissures would include the burn of the seriously injured skin, which resembles a third-degree level. However, there are drugs solely designed to fight this and mostly reduce the effects to a significant degree. The allergy can also be termed as allergic contact dermatitis and is mainly associated with a combination of both chemical (diallyl disulfide) and mechanical (rubbing).

Garlic allergy has been known since around the 1950s; garlic allergy is rarely caused by the ingestion of raw garlic as compared to the other common ones of touching and even rubbing on allergens. 

It has been suggested that wearing gloves can help remediate the effects of allergy garlic. However, some regular gloves do not provide sufficient protection to the wearer, as they can be penetrated by the chemical Diallyl Disulfide (DADS) found in garlic. Therefore, avoiding garlic is the only sure way to be symptom-free.

Garlic Allergy – Symptoms and Cure

Food allergies are common and occur when the human immune system recognizes the proteins in a particular food as harmful and tries to fight it out when they are harmless. It happens not only by consuming the food but also by just the smell of the foods containing it.

There are many foods that some people are allergic to, and garlic is one of them. In the case of allergies, the human body produces immunoglobin and histamine in reaction to the allergen.

This happens because our body identifies the proteins in garlic to be harmful and, in return, releases histamine, which causes the allergy. Some symptoms include itching or swelling of the mouth, tongue or lipsEczemaAbdominal floating drop in blood pressure nausea

Garlic contains allicin, which is an amino acid, and it has anti-microbial and anti-fungal properties. It is available only when garlic is taken in its natural form without being cooked. When cooked, garlic loses its allicin. It is also responsible for the allergies and also flares up some illnesses like asthma and respiratory-related infections.

Symptoms of Garlic Allergy

  • Flatulence or feeling gassy: Garlic is very sulphuric in nature and results in botulism and makes the intestinal tract react profusely. Consuming raw garlic in plenty can hamper your digestion.
  • Garlic causes inflammation in the stomach as a result of which there are stomach bloating, gas, heartburn, and indigestion problems. These are very mild and often do not require much medication and will subside by itself.
  • Nasal Symptoms caused by Garlic: Garlic sometimes causes the stuffy or runny nose to people who are allergic to the garlic dust. These symptoms subside within a short time even without any medicine if the use of garlic is stopped.
  • Skin rashes occur just by touching garlic in some people.
  • However, these symptoms are sporadic and can be easily overcome by taking anti-histamine tablets or some steroids if the need arises.
  • In infrequent cases of a garlic allergy reaction, acute vomiting and nausea may be present – this condition is termed as anaphylaxis. Such situations can be treated with epinephrine. A physician may be consulted for better medical assistance. The best way to avoid exposure to garlic allergy is to stop eliminate its allergen altogether.

 Epinephrine may be needed in severe cases of garlic allergy.

Treatment for Garlic Allergy

Physicians suggest some drugs like anti-inflammatory supplements like bromelain to be taken to treat garlic allergy symptoms. It is advised to be taken twice a day in a dosage of 500 mg. In the case of garlic’s effects on your digestive tract, bromelin is best taken with a meal. In case of allergy from garlic, bromelain may be taken 20 minutes before or after a meal for its anti-inflammatory effects.

It is also suggested to take betaine hydrochloric acid to increase the acid in the stomach, which is responsible for the allergies.

Quercitin has anti-allergic properties and must be taken as advised by doctors. L-glutamine aids in the repair of the lining in the small intestine and enhances nutrient absorption.

Taking Vitamin C tablets can help increase your tolerance levels as it contains bioflavonoids, which might reduce the chances of garlic allergy symptoms.


Onion allergy and garlic allergy may not be prevalent, but for onion-allergic people, it is a huge problem. Allergic people may find it very difficult to control the consumption of onions. Though the US food and drug department have not recognized onion as a significant allergen to an onion or garlic allergic person, it might turn out to be dangerous.

Allergic people may develop the condition of ‘anaphylaxis,’ which causes dizziness, faintness, difficulty in breathing, loss of conscience, hives, rapid heartbeats, and swelling. People suffering from anaphylaxis need immediate medical attention, such as a shot of epinephrine. Allergic people must abstain from onions. This is the most challenging part as almost all major food items are prepared using onions.

Since onion is one of the main ingredients used to make food practically everywhere, living with onion allergy can thus be tricky, and it needs one to be extra cautious to avoid being exposed to them. Here are tips to always consider:

  • Always read the ingredients of processed food before eating
  • Check with the cook before you eat prepare meals
  • Get rid of onions from your house
  • When you realize you have been exposed, call for help immediately

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