Oral Allergy Syndrome

What is Oral Allergy Syndrome?

Oral Allergy syndrome is a cross reacting symptom arise in contact with pollen, raw fruits, vegetables or nuts. This happens due to stimulation of the immune system by the similar effect as pollen during eating of raw fruits, vegetables.

Oral allergy syndrome

The immune system cannot differentiate the protein constituent of the raw fruits, vegetables with pollen. The same food items when cooked become unable to produce oral allergy syndrome, as cooking temperature destroy the responsible protein. Therefore, immune system unable to recognize the food. Synonym of the Oral Allergy syndrome is Pollen food syndrome. (1,2,4)


The prevalence is rare for children; but more common in older children, teens, and young adults. The prevalence of oral allergy syndrome is associated with allergy to birch, ragweed, or grass pollens. But the association is not always same for everyone. (1)


Oral Allergy syndrome comprises symptoms restricted in the oral zone. After swallowing or removing the contacts of allergen, including raw fruits or vegetable from mouth relatively involves quick subsiding of the symptomatic approaches. The symptoms of Oral Allergy syndrome get rid of by their own way. The following are the symptoms of oral allergy syndrome:

  • Itchy mouth
  • Scratchy throat
  • Swelling of the lips
  • Inflammation in the mouth, tongue, and throat.
  • Itchy ears
  • Difficulty of breathing due to severe inflammation of throat. Rarely occur (1,3,4)
  • Anaphylactic shock


Generally, individuals having an allergic reaction in contact with pollen from trees, weeds or grasses have a tendency to develop oral allergy syndrome.

The co-relation between this similar effects arise in both pollen and food items can be explained as the immune system, triggering proteins present in pollen, grass or weeds have similar structural analogous protein present in the raw fruits, vegetables, nuts and some spices. These proteins provide a defensive mechanism for the plant and essential component for the growth of the plant. (2)

The Nature of Allergic Reaction

The triggering factors is not same for every susceptible individuals. Some people have susceptibility only against one food item, but some have complained that certain varieties of food trigger the allergic reaction; for example, different varieties of apples.

Even some individuals have a connection with seasonal allergic reaction, like in the spring season, birch tree pollen is a causative factor for allergic reaction to the susceptible individuals. Those people also have similar seasonal food allergies, including carrot, peanuts, hazelnut and almond.

Similar effect arises with individuals having a reaction against grasses can react with peaches, tomatoes, celery, melons and oranges. The following brief section describes the similar reaction with different pollen and food items.

Similar properties between different pollen and food items

  • Birch pollen: apple, cherry, peach, pear, kiwi, plum, carrot, celery, almond, hazelnut
  • Grass pollen: tomato, oranges, celery, melons, peaches
  • Ragweed pollen: banana, melons, cucumber, zucchini, sunflower seeds (1,2,3)


There is no specific test for oral allergy syndrome. The clinical history is important for detecting the oral allergy syndrome. Some doctor has also ordered skin prick tests and oral food test with raw fruit or vegetables.

The oral allergy syndrome is not having serious health hazard, if the reaction is restricted in the oral zone only. But, if the reaction beyond the mouth region and provides systemic symptoms, then it is considered as anaphylaxis. Anaphylaxis can provide serious health hazard. This type of reaction need detail diagnosis to provide specific management for future control. (2,3)


Oral allergy syndrome may not provide a fatal outcome and self controllable. But it is suggested that consult with general physician for confirming the symptoms are related to oral allergy syndrome.

Self Management

  • If reaction develops, do not panic. Be calm and wash mouth with plain cold water and take a rest.
  • Some cases, a hot drink without providing blistering effect can diminish the residual effect of allergen.
  • In case of anaphylactic shock, the doctor may prescribe an epinephrine auto-injector to control such possible severe reactions.
  • Anti-allergic medicine like cetrizine, which has anti-histaminic effect can control the unpleasant effect.
  • If the symptoms persist more than an hour, then medical assistance may require, as that indicates anaphylaxis.
  • Urgent adrenaline shot require to control anaphylaxis. (1,2,3)

Precautionary Measures of Oral Allergy Syndrome

  • Avoidance of taking food, which can cause allergic reactions.
  • Avoid to take raw food items
  • Try to identify the food items which provide allergy and also avoid similar types of food items.
  • Use plastic gloves and mask during preparation of food (3)


  1. Oral Allergy Syndrome; Retrieve from: http://acaai.org/allergies/types/food-allergies/types-food-allergy/oral-allergy-syndrome
  2. Oral Allergy Syndrome (OAS); American Academy of Allergy, Asthma &Immunology; Retrieve from: https://www.aaaai.org/conditions-and-treatments/library/allergy-library/outdoor-allergies-and-food-allergies-can-be-relate
  3. Oral Allergy Syndrome or Pollen-Food Syndrome; Retrieve from: https://www.allergyuk.org/oral-allergy-syndrome/oral-allergy-syndrome
  4. Jarrod Breeze; Foods That May Trigger Pollen Allergies; Retrieve from:http://www.webmd.com/allergies/features/oral-allergy-syndrome-foods

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