Misunderstanding allergies

Posted on 1 October 2013

The misunderstandings around allergies are almost as common as allergies themselves. Mariana Lloyd, chemical pathologist at PathCare Laboratories at Mediclinic Bloemfontein, answers two frequently asked questions.  

I’m intolerant to a certain food; does this mean I’m allergic?
Some of the symptoms of food intolerance and food allergy are similar, but they’re two different conditions. Food intolerance occurs when the digestive system cannot digest a particular food or foodstuff. Common examples are lactose intolerance (which is due to a deficiency in the lactase enzyme) and reactions to food additives, like sodium benzoate, MSG or tartazine. Food intolerant individuals can often eat small amounts of the food in question without a problem and the reactions are seldom life-threatening. But the diagnosis of a food intolerance may be difficult to make, as the symptoms are usually vague and may sometimes occur hours, even days, after ingestion of the food. An accurate history of repeated reactions to certain foods remains the cornerstone of the diagnosis. ??Compare this to a food allergy, a very specific immune system response to a particular food protein or allergen. Unlike with intolerance to food, a food allergy can cause serious or even life-threatening reactions when a person ingests even small amounts of the food they are sensitised to. Common food allergens include, egg, milk, fish, shellfish, soy, wheat, peanut and tree nuts. Together with a good clinical history, laboratory tests and investigations may assist in confirming the causative allergen in a case of food allergy.

Are children more likely to get allergies and if my child has an allergy will he outgrow it?
While some adults may develop allergies for the first time in adulthood, children are more likely than adults to develop food allergies in general. Consider this: the prevalence of food allergies during the first year of life is estimated to be six to eight percent in Western countries, with a prevalence of two to three percent in older children and one percent in adults. One possible explanation for this is related to the ability of many food-allergic children to develop immune tolerance to the food allergens as they grow.

Some children outgrow their allergies, while some childhood allergies will persist into adulthood. Children typically outgrow wheat, egg, soy and milk allergies. But allergies to peanuts, tree nuts, fish and shellfish can persist into adulthood. Hay fever (inhalant allergies) also tends to continue into adulthood. The oral allergy syndrome (OAS, also known as pollen-food syndrome) can also occur in older children and adults who have had pollen allergies and start showing a cross-reaction to foods ingested. This is because pollens may contain proteins of a similar structure to those found in particular foods (e.g. fruits, vegetables, nuts and beans). This may cause swelling, itching and redness in and around the mouth area when the child or adult ingests the food in question.

You can read more about pet allergies here.

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The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.