Food Allergies: Causes, Symptoms & Prevention Explained

Food allergies affect approximately eight per cent of children below the age of five and four per cent of adults. However, many children get rid of the allergy as they grow older. The severity of food allergy can range from minor abdominal pain to life-threatening conditions like anaphylaxis.

Food allergies happen when reactions occur in the immune system after eating certain foods. The symptoms show up even if you eat a very little amount of those allergy-causing foods. Moreover, it can lead to severe symptoms and life-threatening conditions like anaphylaxis in some cases.

Note: People easily confuse a food allergy with food intolerance. Food intolerance is a more common condition and does not affect the immune system. Moreover, it is less severe than food allergies.

The common types of food allergies are –

• Immunoglobulin Mediated Food Allergies: This type arises when certain food reacts with the IgE antibodies produced by the immune system. It is most common in children and infants. Examples of this type of food allergy are oral allergy and cross-reactivity syndrome.
• Non-Immunoglobulin Mediated Food Allergies: When the reaction in the immune system happens without the involvement of an antibody, it is known as non-immunoglobulin mediated food allergy. Eosinophilic esophagitis, food protein-induced enterocolitis syndrome and allergic proctocolitis are examples of non-immunoglobulin mediated food allergies.

The common symptoms of food allergy are as follows –

• Itching or tingling sensation in the mouth
• Itching, hives or eczema
• Swelling of face, lips, throat or other body parts
• Nasal congestion, breathing trouble or wheezing
• Diarrhoea, nausea, vomiting and abdominal pain
• Light-headedness, dizziness or fainting

When someone has a food allergy, the immune system identifies a certain food as a potential danger. In response, it releases an antibody called immunoglobulin E to neutralize the allergen. 

When the person eats that food, the immunoglobulin E senses it and releases a chemical known as histamine and other chemicals. These chemicals adversely causes the signs and symptoms of food allergies.  

Most food allergies are a result of certain proteins present in-

• Shrimp, crab and lobster
• Peanuts
• Pecans and walnuts
• Fish
• Chicken eggs
• Cow’s milk 
• Wheat
• Soy

The following individuals are at risk of food allergies–

• Individuals with a family history of asthma, hives, eczema or hay fever.
• People who already have an allergy to certain foods are at higher risk.
• These allergies are more common in infants and toddlers.
• Individuals with asthma are more vulnerable to food allergies.

To diagnose food allergy, your doctor may –

• Ask you about the symptoms of the allergy
• Enquire about your family history
• Recommend skin prick test and blood test
• Ask you to eliminate certain foods from your diet
• Recommend oral food challenge

The best treatment for food allergies is identifying the allergen and eliminating them from your diet. Keep emergency medications like epinephrine auto-injectors, antihistamines and corticosteroids available for accidental reaction and ingestion. Emergency medical care is necessary after the use of an epinephrine auto-injector.

This section provides a list of methods on how to prevent food allergy  –

• Make sure to read the labels of food before eating it.
• Wear a medical alert bracelet to let others know a condition you are unable to communicate.
• Talk to the doctor for prescribing epinephrine for emergency situations.
• While at a restaurant or eating outdoors, make sure that the chef knows the food you cannot eat.
• Plan the snack and meals before leaving your home.

Traditionally, there is no cure for food allergies. However, oral immunotherapy gives hope, and individuals can treat the signs when they arise. Identifying and avoiding the foods that cause the symptoms are still the best way to treat and prevent food allergies.