Food allergies are a group of closely related responses that involve an allergic reaction to a specific food. Roughly 1 to 2 percent of adults and 3 to 8 percent of children are estimated to have true food allergies, according to Asthma and Allergy Foundation of America.

An allergic response to a food or food ingredient involves the immune system’s exaggerated response to a food protein. The body produces immunoglobulin E (IgE) antibodies against the food. These IgE antibodies attach to the body’s mast cells, a type of white blood cell that contains chemicals called histamines and leukotrienes.

The next time IgE antibodies come in contact with the offending food molecule, these chemicals are released, causing symptoms ranging from mild (e.g., itching, hives) to severe and life-threatening anaphylactic shock, which is characterized by difficulty breathing and dangerously low blood pressure.

There is no way to know whether a person with a food allergy is likely to have a mild or severe reaction after eating the problem food. Reactions can be fatal and individuals with a food allergy must completely avoid all foods to which they are allergic. Food allergies can be triggered by even tiny amounts of a problem food.

It is important to note that allergic individuals do not necessarily have to ingest a food allergen to have a reaction. Even touching another person who has recently consumed a problem food can bring on a reaction in some people. These sensitive individuals must be very careful not to have skin contact with any type of product containing the allergen and should also be careful not to inhale fumes produced by the food.

There are several conditions that may predispose an individual to develop food allergies. People with a family history of hay fever, asthma, hives or eczema have an increased likelihood of having a child who will develop food allergies. Age is also a factor. Although food allergies affect people of all ages, they are most common in toddlers and infants.

Several food allergies that are typically prevalent in children gradually go away as children grow older. For instance, food allergies to milk, eggs, wheat and soy, are common in the first few years of life, but are often outgrown over the next 10 years. This is because the body is less likely to absorb food proteins that trigger allergies as the digestive system matures over time.  

However, certain food allergies, such as those related to peanuts, tree nuts, fish and shellfish, are likely to persist throughout adult life. Food allergies can also develop during adulthood. Unlike children, adults do not usually lose their sensitivity to food allergens.

It is important to note that not all reactions to food are allergic reactions. Related issues that may be confused with food allergies include food intolerances, food poisoning, sensitivity to food additives and other problems.