A food allergy is when the immune system experiences an adverse reaction to specific proteins found in food.
Symptoms of a food allergy can range from moderate, such as tingling in the mouth and a skin rash, to life threatening, such as a severe swelling of the throat that makes it difficult to breathe. A life-threatening allergic reaction is known as anaphylaxis.
Food types
Any food can potentially cause an allergic reaction, but there are eight types of foods that are responsible for 90% of all food allergies.
In children, the foods that can cause an allergic reaction are:
- eggs,
- milk,
- soya,
- wheat, and
- peanuts.
In adults, the foods that can cause an allergic reaction are:
- crustaceans (shellfish), such as crab, lobster and prawns,
- tree nuts, such as walnuts, brazil nuts, almonds and pistachios,
- peanuts, and
- fish.
How common are food allergies?
Food allergies are common, but they are not as widespread as many people think.
A number of surveys have found that 1 in 5 people claim to have a food allergy. However, a Food Standards Agency (FSA) report in 2008 estimated that only 5-8% of children and 1-2% of adults have a food allergy. Some researchers believe that the figure for adults may be slightly higher, at around 3-4%.
The reason why many people may claim to have a food allergy is that they mistake an intolerance to certain types of food (which does not involve the immune system) for a food allergy (which does).
For reasons that are not fully understood, rates of food allergy cases (but not deaths, see below) have risen sharply over the last two decades. See Causes for more information.
A common misconception
Another widely held misconception is that deaths resulting from food allergies are widespread. This is possibly due to the fact that, when these types of deaths occur, they receive a lot of media coverage.
Outlook
Most children will ‘outgrow’ food allergies to milk, eggs, soya and wheat by the time that start school.
Peanut allergies are usually more persistent. An estimated 80% of children with peanut allergies remain allergic to peanuts for the rest of their life.
Food allergies that develop during, are first noticed in or persist into adulthood are likely to be lifelong allergies.
There is no cure for food allergies. Treatment involves identifying the specific food that triggers the allergic reaction and then avoiding it.
If accidental exposure to an allergy-causing food occurs, anti-allergy medications can be used to relieve the symptoms. In cases of mild to moderate allergic reactions, medications such as antihistamines (which block the effects of a protein called histamine) can be used.
In the case of a severe anaphylactic reaction, an injection of a medication called adrenaline is required. As a precaution, people who have previously experienced an episode of anaphylaxis are often given an adrenaline injection device to carry with them.