What is Oral allergy syndrome symptoms, causes and risks


Oral allergy syndrome is one kind of allergic reaction that mainly affects your mouth, lips, tongue, and throat. It is somewhat the same as allergic rhinitis, also called hay fever. Here your body will cross-react to some proteins in some specified foods. These proteins are the same as those found in the pollens, which are associated with seasonal allergies and hay fever. Because these foods are available throughout the year, oral allergy syndrome is not seasonal.


Cause of oral allergy syndrome

You can find proteins in all kinds of organic matter. Our body's immune system recognizes specified proteins for targeting bacteria, viruses, and other germs. But sometimes recognizes everyday proteins also. When you eat those proteins, which are available in large amounts, your body sometimes starts recognizing them as abnormal. The body then starts reacting by giving a substantial immune response, leading to swelling or other allergic symptoms and discomfort.

For many people, the vital signs of oral allergy syndrome are swelling and itchiness in the lips, tongue, throat, and mouth just after eating some food.

There are a variety of fruits and vegetables that can cause oral allergy syndrome. Such as

  • Fruits: Prunes, Apples, Mangoes, Bananas, Avocados, Figs, Strawberries, Kiwis, Watermelons, Oranges, Apricots, and Raspberries
  • Vegetables: Celery, carrots, cumin, Fennel, Tomatoes, Corn, Peas, Peanuts, Chickpeas, Soy, Almonds, Lentils, and Honey



Symptoms of oral allergy syndrome start only after consuming certain kinds of foods. Usually, symptoms vary and might peak at various stages of life.

Some of the symptoms include

  • Itching of throat, tongue, mouth, and lips
  • Swelling mainly of tongue and lips
  • Nausea and vomiting
  • Hives
  • Asthma


Diagnosis of an Oral Allergy Syndrome

Diagnosis of oral allergy syndrome mainly includes various steps and involves clinical and laboratory methodologies.



These methods are prevalent where diagnosis needs the approval of allergic rhinitis in addition to itching and tingling that starts after consuming some fresh fruits and vegetables. In many cases, proper patient history shows the link between drinking a specified food and the start of swelling or tingling. In some cases, the doctor might advise an elimination of that specific food in the diet,  that the concerned person has to avoid. 



Laboratory diagnosis tests mainly involve skin testing through prick, scratch, or even blood tests. For skin testing, a dermatologist will mark some grid on your back or forearm and then put on the things or suspected food that causes allergies. If any mark develops on the skin, it is measured after minutes to know about the level of reaction. 

When prick tests with pollen come positive, however, the food does not provoke any reaction; the person is asked to eat some amount of the food that is suspected of causing allergies. If there is a reaction just after eating the food, it confirms that there is oral allergy syndrome.

In several cases, blood tests are done to diagnose the condition. At first, the doctor does a test to know about the antibodies level in your blood. Then another test is done to check specified antibodies. A blood test is done when a skin test is not possible.



There are no treatments for this syndrome, and the only option is to avoid the food that causes allergic symptoms. Proper diet management ensures people with this syndrome can lead an everyday life. When there is an allergic reaction, the first treatment mainly involves rinsing your mouth with water and resting. Hot drinks also help in destroying some of the proteins or inactivating them.

An antihistamine will take about 1-2 hours to work, and the effects of oral allergy syndrome start wearing off after 30 minutes. But antihistamines can prevent the results from lingering and must be well taken care of.

Sometimes, it is possible to decrease the immune system's sensitivity to several allergens through allergy shots or immunotherapy. This is relevant when one allergen is involved. Those therapies that are under the skin delivery are one of the good options for treating oral allergy syndrome.



In many cases, cooking those foods that cause allergies can destroy the proteins causing oral allergy syndrome. Some foods are the exception to it, such as nuts and spices. Nuts consist of various allergens which are not destroyed by heat. The same rule applies to celery.

Fruit juices, when pasteurized, are okay as they are heat treated. But some of the smoothies might contain raw and unpasteurized juices or purees. This must be avoided when any of its ingredients are active triggers.

In maximum cases, it's best to avoid the food, but some methods people can try to enjoy their favorite food without getting allergic symptoms, such as:

Microwaving the food slightly: Here, the primary protein responsible for the reaction is removed. You have to microwave the fruit for about 1 minute and then chill them immediately, reducing the effects of the oral allergy syndrome.



People who suffer from oral allergy syndrome often find that their symptoms start worsening at the time of pollen season. Therefore, they wish to avoid the trigger foods altogether during the peak season. If you are unsure how to manage it, then the best option is to consult a good dentist who can advise you best on this matter.  MyDentalPlan is a platform where you can find hundreds of skilled dentists as per your preference.



About the Author:

Suprithi Choudhary, M.Pharm (Pharmacology) Medical Content writer

Suprithi is a Pharma Professional working as a medical content writer and previously worked as a Research Scientist and Senior Research Analyst


  • C.M Academy
  • Attended the Panjab University- Chandigarh, Pharma post-graduate in Pharmacology

Special thanks to Dr Deepak Kulkarni, a dental surgeon with over 23 years of experience who proofread this blog. He graduated from the H.K.E's Dental College, Gulbarga, and has certifications in ACHS International Accreditation Education Plan; Advanced Rotary Endodontic - Restorative Continuum; and Leadership, Team Building and Customer Service Leadership from the Oscar Murphy International.

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