Oral Allergy Syndrome Explained
Last Updated: 3rd February 2023 · Written by Kate Young
Also known by the abbreviated form of ‘OAS’, Oral Allergy Syndrome is a condition that can result in an allergic reaction in the mouth after eating. OAS has a classification as a ‘cluster’ of reactions and happens when someone eats particular types of food. Those with OAS tend not to have it from birth, rather they develop it later in adulthood, just as many do with Hayfever.
OAS is arguably the most prevalent allergy caused as a result of eating food, but ironically, it’s not actually a food allergy to a specific foodstuff. What it actually is, is a cross-reaction caused by traces of different varieties of weed or tree pollen, commonly found in some fruits and vegetables. As a result of this, OAS typically only affects those who also have pollen allergies at certain times of the year, especially when the reaction is to tree pollen.
One major disadvantage of OAS (other than the obvious) is that raw fruit and vegetables are off the table. So, no more carrot sticks or nice, crisp Granny Smith apples, as the ingestion of fruit and veg can only be done after it has been baked or boiled, which destroys the offending pollen contained inside. That is, unless you are talking about celery or nuts, which can cause a reaction whether cooked or otherwise.
It’s not all bad news though, as if you think you might have the condition, it’s easy to get tested for it. At Lifelabtesting.com, we perform affordable and comprehensive blood testing services to our clients that screen for possible allergens that might provoke an immunoglobulin E (Usually written as IgE) response, the same type that is encountered by sufferers of OAS.
For as little as £75, you can get yourself checked out and start taking steps to minimise the effect of this debilitating condition.
The signs of OAS can come on quite suddenly and be provoked by a wide range of fruits and vegetables. Usually within minutes of ingestion, a burning or itching sensation is experienced in the ears, pharynx (the cavity behind the nose and mouth), lips and mouth. It can also manifest in the eyes, nose or more worryingly as a tightness in the throat.
OAS can develop into anaphylactic shock, but it doesn’t happen very often at all. More usually, there is a mild reaction which happens when the allergen in fruit and veg isn’t eliminated by gastric acid in the stomach and a histamine release occurs later in the intestines. This can then cause acute indigestion, cramps, vomiting, diarrhea, hives and in some cases, low blood pressure.
In the individuals that suffer with OAS, the foods that cause it can vary greatly. In some, there will be one particular trigger, whereas others might have to avoid different types of raw fruit and veg. The one common theme however, is that the attacks are usually accompanied by a reaction to higher, seasonal levels of pollen.
To complicate things further, under the umbrella of OAS, there are different categories of pollen that cause a reaction to different types of people.
❏ Ragweed pollen, found in bananas, cucumbers and green peppers
❏ Grass pollen, in tomatoes, oranges and peaches
❏ Mugwort pollen, present in carrots, fennel and sunflowers
❏ Birch pollen, found in avocados, cherries and apples
❏ Alder pollen, existing in hazelnuts, raspberries and pears
So, as you can see, OAS is a complex beast and takes some work to get to the root cause (no pun intended). The only quick and easy way to solve the puzzle and start enjoying food again, is to get yourself screened. You’ll then know what you’re dealing with and you’ll be able to create a strategy to minimise the effects of your allergies.
Head on over to our website to find out more or have a ‘live chat’ with one of our friendly experts and take your first steps to a freer food life.