THE ORAL ALLERGY SYNDROME
This is a syndrome of allergic sensitization to a variety of fruits, vegetables, and nuts. Symptoms are principally oral and peri-oral, but may be experienced in other organs. The mechanism is believed to be through cross-allergenicity of some foods with a pollen to which the individual has immediate hypersensitivity. The number of specific food triggers listed for each pollen is likely to increase in the future.
Principal groupings of foods with major pollens allergies:
Birch: almond,apple,apricot,brazilnut,carrot,celery,cherry,coconut,fennel,hazelnut,kiwi,nectarine,peach,peanut,pear,plum,potato,swede,tomato,walnut.
Grass:
kiwi,melon,orange,tomato,watermelon.
Ragweed:
banana,cantaloupe,cucumber,honeydew,watermelon,zucchini.
Most patients report itching of the mouth and throat with one or more of the members of the pollen/food group. In the case of fruits and vegetables, it is often restricted to the uncooked food. Symptoms of rhinoconjunctivitis, asthma, hives and angioedema, vomiting, or abdominal pain are more rarely reported after ingestion. Hazelnut may cause life-threatening anaphylaxis. Potato is quite distinct and causes symptoms of rhinoconjunctivitis or asthma only when being peeled or scrubbed.
One report found that amongst patients seen in a referral-based allergy clinic, of those that were birch-sensitive, 50-93% were symptomatic on exposure to apple and/or hazelnut. Without birch-sensitivity, only 6-7% were sensitive to these foods.
Although the symptoms are typically localized to the mouth and throat, up to 4% of patients with this syndrome may develop more severe systemic symptoms. Up to 4% of patients may have gastrointestinal symptoms such as abdominal pain or vomiting.
The best treatment for this syndrome is avoiding the foods that cause symptoms. There are some studies showing that allergy shots or vaccinations may improve the symptoms of oral allergy syndrome.
