Does your teenager suffer from hay fever?
Does he complain that certain fruits or nuts make his whole mouth feel itchy, his tongue swollen or his throat scratchy?
Does this mouth discomfort only last for a few minutes and then resolve on its own, often not requiring treatment?
Is this reaction confined to his mouth without any associated chest problems such as wheezing, or a skin rash, or diarrhoea and vomiting?
Then perhaps your teenager suffers from a condition called Oral Allergy Syndrome (OAS)
OAS, commonly known as Pollen-Food Syndrome, is an allergic condition that occurs generally in older children, teenagers or adults. OAS sufferers have hay fever, experiencing a runny nose and itchy watery eyes when exposed to certain pollens. The body sees the allergen -the pollen – as harmful and mounts a heightened, inappropriate response resulting in this picture of nasal congestion. People with OAS complain that certain fruits and nuts cause them discomfort in their mouths such as itchiness of their tongues or a scratchy sensation in their throats. The allergy is due to local contact with the offending fruit or nut resulting in only the mouth being affected. These two seemingly unrelated symptoms, the hay fever from pollen, and the mouth itchiness from fruit, are linked due to the fact that fruits, nuts and pollens share similar proteins which cause allergic reactions. This means that a person with a rye grass allergy may experience a tingling palate when eating watermelon. Or someone allergic to birch pollen may complain that apples and pears give him a scratchy throat. It therefore makes sense that OAS is generally more prominent during pollen season.
How can a diagnosis of OAS be made?
A careful history should be taken showing the typical symptoms – the hay fever as well as the mouth itch following eating certain fruits.
The offending fruit or nut can be given in the rooms under supervision – an oral food challenge – to observe the symptoms.
Skin prick tests to pollens can be done. This means that drops of diluted allergens are placed on the arm and then pricked with a lancet to see if there is a reaction. A positive result causes a mosquito-bite type of lesion within a few minutes. In OAS these will most likely show a positive result to certain pollens.
Skin prick tests using fresh fruit can also be done and may cause a reaction too.
OAS symptoms may improve if certain fruits are cooked. Interestingly, cooked food doesn’t cause a reaction as the heating process distorts the protein and the body doesn’t recognize it as an allergen. Peeling fruits may reduce the allergen content of the fruit too. For local mouth reactions, an anti histamine will help as well as rinsing with water after eating.
Treatment of the allergic rhinitis definitely reduces symptoms in OAS. This includes taking an anti histamine and a steroid nose spray prescribed by your doctor. Long term treatment for allergic rhinitis may include immunotherapy. This is treatment in the form of drops that are put under the tongue daily for up to 3 years. This results in the immune system actually changing so it no longer see the specific pollen as harmful, and essentially eradicates the allergy.
If you would like to take away the itch from your litchi-eating experience, then consult your allergy doctor!