Oral Allergy Syndrome: Causes and Symptoms

oral allergy syndrome causes and symptoms

Most of us are familiar with allergy season, that time of year when pollen irritates the noses of certain people. It triggers sneezing, coughing, a runny nose, itchy eyes and in some cases headaches. These are what you would call “typical” symptoms, but have you ever heard anyone complain about having an itchy mouth?


If you have, it’s possible the person has oral allergy syndrome.

Link between pollen and oral allergy sufferers

link between pollen and oral allergy syndromeThe American Academy of Allergy, Asthma and Immunology reports that up to one-third of pollen allergy sufferers also have oral allergy syndrome. Oral allergy syndrome is an allergic reaction to certain proteins in fruits, vegetables and nuts. When a certain food is consumed, the immune system notices the pollen and similar proteins in the food and signals an allergic reaction to it. Oral allergy syndrome is often associated with birch-pollen allergies; however, it also affects those who have allergies to pollen from grass and ragweed. Although these reactions can occur at any time of the year, they are worse during pollen season.

Doctors don’t know why, but for some reason oral allergy syndrome doesn’t seem to appear in young children. It tends to happen to people when they are closer to their teens or are young adults. Typically this means they have been eating the fruits and vegetables for years without having any problems then all of a sudden they have the oral allergy.

Symptoms of Oral Allergy Syndrome

When someone has oral allergy syndrome (OAS) the symptoms often occur within minutes of eating or touching the fruit, vegetable or nut, yet in some cases the symptoms don’t show up until more than an hour later. Some people with OAS have reported getting a rash, itching or even swelling where the food touches their skin. This usually happens when they peel the offending fruit or vegetable.

The typical symptoms of oral allergy syndrome include itchy mouth; scratchy throat; as well as swelling of the lips, tongue and throat. Sometimes their ears get itchy. The symptoms usually go away quickly so treatment is not necessary; however, more serious reactions can happen, such as swelling of the mouth, pharynx and windpipe; hives, vomiting and diarrhea. In these cases, people should seek immediate medical attention.

4 types of pollen associated with oral allergy syndrome

type of pollenThere is nothing more inviting than fresh fruits and vegetables, especially during the spring and summer months, but for those who have allergies, paying close attention to the food that comes into the house is important.

It is true that not everyone with pollen allergies will have oral allergy syndrome, but it is helpful to know that the following foods are linked to these allergens:

  • Birch pollen: Apples, almonds, celery, cherries, kiwis, peaches, pears, plums, carrots, and hazelnuts.
  • Ragweed pollen: Melons, bananas, cucumbers, zucchinis, and sunflower seeds.
  • Grass pollen: Melons, peaches, oranges, celery, and tomatoes.
  • Mugwort pollen: Apples, melons, watermelons, carrots, and celery.

There is no cure for allergies. The only defense is avoiding triggers, as well as being able to recognize and manage allergic reactions. Medical researchers around the world continue to investigate every possible angle when it comes to allergens and the human body. It seems as if they are discovering new triggers every day, but also more questions.

The mystery of trigger foods and allergies

For example, there are certain foods they know people should flag (be aware of) if they are allergic to certain pollen or substances. In recent years, researchers concluded that people with birch pollen allergies might react to coriander, fennel or parsley. They also discovered that like pollen allergy, people allergic to latex rubber may react poorly to exposure to bananas, avocados, chestnuts and papaya, but they aren’t certain why. Lastly, if ragweed is an issue for you, dandelions, echinacea and chamomile tea might also cause an allergic reaction.

How preparing foods different ways can stop allergies

If you have allergies to a certain food there is still the possibility you can eat it in a different form. Take the apple as an example. While people who are allergic to apples will want to avoid eating a fresh apple, they may not have any reaction to apple juice or applesauce. This is because the allergy causing protein is broken down during the cooking process.

In some cases, just peeling the fruit can make it possible for people, who are normally allergic to the food, to go ahead and consume it. Dieticians tell us that this happens because in some fruit and vegetables the allergen is actually concentrated in the skin.

Food experts also point out that some people with food allergies can still consume the offending fruit or vegetable without experiencing an allergic reaction if it is canned or frozen.

If you experience an itchy mouth after consuming food, speak to your doctor. A diagnosis of oral allergy syndrome can be determined following a clinical history review and after conducting skin prick tests, as well as oral food tests.

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