Food allergy is the term used for an allergic reaction triggered by the immune system of the body after consuming certain food items. Eating even a small portion of allergy causing food can lead to development of hives, swelling of airways, and even anaphylactic reaction in some people.
It is important to understand that food allergy is an entirely separate entity from food intolerance. The latter is generally confined to the gastrointestinal tract, does not involve the immune system and is a less serious problem.
Prevalence of food allergy
It is believed that 6% to 8% of all children under the age of three and 3% of all adults suffer from some kind of food allergy. Although there is no cure for this condition, the food allergy gets cured spontaneously in some children.
Symptoms of food allergy
The symptoms of food allergy may develop within minutes in a person who is severely allergic to a few hours in individuals who are less allergic.
The common symptoms of food allergy include:
- Itching in and around the mouth
- Development of hives
- Swelling of the lips and throat
- Watering of eyes
- Difficulty in breathing
- Pain in abdomen
- Loose motions
- Nausea and vomiting
- Lightheadedness and fainting
In certain individuals, the food allergy is so severe that it may trigger an anaphylactic reaction. The symptoms of this reaction are:
- Constriction of airways
- Heaviness in chest with difficulty in breathing
- Sudden drop in blood pressure
- Cold, clammy skin
- Rapid pulse rate
If not treated urgently, it can prove fatal.
Causes of food allergy
In certain individuals, the immune system mistakes a particular food to be an allergen and produces immunoglobulin E antibodies against it. The next time the person consumes the same food item, the IgE antibodies already present in the blood stream sense it immediately and trigger an allergic reaction. This involves release of a chemical called as histamine which is responsible for producing the symptoms related to food allergy.
Common food items that produce food allergy
Food allergy is usually due to specific proteins present in the food items. Some of the food items that are known to induce allergic reaction are shellfish, walnuts, fish, eggs, peanuts, milk and wheat.
Risk factors for food allergy
Some of the common risk factors for food allergy include:
- Family history: a person is more likely to develop food allergy if he has a family history of or hay fever.
- Food allergy in the past: in children, food allergies may resolve on their own but often come back in adulthood.
- Age: Food allergies are more common during childhood. As children grow up, the possibility of absorption of allergens decreases. Allergy to milk, wheat and eggs usually resolves with age. However, allergy to shellfish and nuts usually lasts for a lifetime.
- Other allergies: Food allergies are common in individuals suffering from other allergies like asthma and hay fever. Similarly, asthma and hay fever are more likely to develop in individuals suffering from food allergies.
Complications of food allergy
Food allergy can give rise to complications like:
- Anaphylactic reaction
- Migraine due to release of histamine
Treatment of food allergy
Antihistamines are usually prescribed to treat cases of mild food allergy. However, in case of severe food allergy, injecting epinephrine is the only way to save the life of the patient. It is advised that people suffering from food allergy carry an epinephrine auto injector with them at all times.