A food allergy is a condition in which consumption of a certain food item can trigger an unusual immune response, caused by immunoglobulin E (IgE) antibody wherein the body’s immune system mistakenly treats proteins found in food as a threat. While food allergies are quite common, they can also be life threatening when these involve respiratory and/or cardiovascular distress. Although it is possible for any food to cause an allergy, there are some common ones like shellfish and nut allergies in adults, and milk, eggs, fish, peanuts and other nuts in children.
“Food allergies are mostly developed during childhood (children under the age of 3) but can develop at any age in life. Food allergies that develop during adulthood, or persist into adulthood, are likely to be lifelong allergies,” said Deepti Khatuja, head clinical nutritionist at Fortis Memorial Institute, Gurgaon.
Symptoms of food allergy
Khatuja notes the following as common symptoms of a food allergy:
- an itchy sensation inside the mouth, throat or ears
- a raised itchy red rash (urticaria, or “hives”)
- swelling of the face, around the eyes, lips, tongue and roof of the mouth (angioedema)
Difference between food allergy and intolerance
A food intolerance is difficulty digesting certain foods and having an unpleasant physical reaction to them. It causes symptoms such as bloating and tummy pain, which usually happen a few hours after eating the food, and does not include the immune system. The symptoms are triggered only if a substantial amount of the food is consumed, unlike an allergy, where just traces can trigger a reaction, said Khatuja.
Is it possible to outgrow a food allergy?
A lot of people often outgrow food allergies, but it also depends on what they are allergic to. While eggs, cow’s milk, wheat and soya allergies can be outgrown, allergy to peanuts, tree nuts, fish, and shell fish tends to persist. “An infant’s digestive tract absorbs immunity boosting immunoglobulins from mother’s milk by a process called pinocytosis or cell drinking. By this process the baby gets readymade antibodies made in the mother’s body to fight off infections,” Dr Suven Kalra, consultant ENT, Max Super Specialty Hospital, Shalimar Bagh, told indianexpress.com.
He added, “Due to this same phenomenon, sometimes proteins causing allergic reactions such as those found in peanuts or eggs are absorbed by the child’s gut without being first digested or broken down into amino acids which triggers an allergic reaction. As a part of normal growth process, a child’s reliance on readymade antibodies from the mother decreases and this pinocytosis stops. Hence the child ‘outgrows’ her allergy.”
Factors that make it more likely that a food allergy will persist includes having a larger SPT (skin prick test), wheal size or higher food-specific IgE level, having other comorbid allergic diseases, having more severe symptoms on ingestion, said Khatuja.
Dr Kalra also shared that oral immunotherapy is a type of treatment in which a person is encouraged to consume the very thing that he/she is allergic to in small quantities and gradually increasing the amount. “By this process the immune system gets de-sensitized and the person in a way outgrows the allergy. However, it must be done in a controlled environment under a doctor’s supervision as it may cause a severe reaction,” he added.