Food allergies are a response by a person’s immune system to a food or food component it perceives as a threat. After a susceptible person ingests a problem food, the immune system reacts with the release of histamines and other chemicals that trigger symptoms ranging from mild to severe.

Individuals who have a food allergy should work closely with their physicians to better understand their condition and its causes. A food allergy can result in a fatal reaction if not treated properly. Once individual food allergens (any food component or additive that is mistakenly perceived as a threat, triggering an allergic reaction) have been identified, people must begin the difficult task of removing all forms of that food from their diet.

The most commonly allergenic foods, along with their more popular forms, include (Note: This is not a complete list):

• Milk. Includes cheese, butter, cream, casein (a milk protein) and whey.
  
  
• Wheat. Includes crackers, pastas, bread and malt.
  
  
• Soybeans. Includes lecithin (a food ingredient often made from soy), some types of baked foods, canned tuna, sauces and baby formulas.
  
  
• Peanuts. Includes peanut butter, "gourmet" peanut oil (includes cold-pressed, expelled or extruded), many types of ethnic foods (including Chinese, Indonesian, Thai, Vietnamese, and possibly Mexican) and some flavorings.
  
  
• Tree nuts. Includes hazel, cashew, almond, sesame seed and Brazil nuts.
  
  
• Shellfish. Includes crab, crayfish, shrimp and lobster.
  
  
• Fish. Includes yellowtail, salmon, mackerel, tuna and hake.
  
  
• Eggs. Includes commercially processed cooked pastas and some brands of egg substitutes.

After visiting a physician and identifying which foods are most likely causing the reaction, individuals need to work to remove those foods, products that contain those foods and all derivatives of those foods from their diets. Removing a problem food from the diet is a way to prevent the allergic chain of events – known as the allergic cascade – from ever occurring.

Many types of food allergies can be triggered by just a trace amount of the food. Reactions can occur when a person eats a food that was prepared on the same surface as a problem food, or when the gases or fumes produced by cooking a problem food are inhaled.

Removing a specific food from the diet is often very difficult. Besides avoiding the food itself, individuals need to avoid any foods derived from the problem food. This often requires the allergic individual to memorize (or carry with them) a long list of alternate food names. For example, albumin is a derivative of chicken eggs that contains egg proteins that can trigger an allergic reaction in individuals with egg allergies. 

It is very important for individuals with food allergies to learn the name of every dangerous food derivative. New legislation may make it easier for people to determine if a food item contains a potential allergen. As of January 2006, food manufacturers are required by the Food and Drug Administration (FDA) to clearly list food allergens on their product labels.

With young children, some physicians believe it may be possible to avoid sensitization to food allergens by waiting to introduce some food types. While a controversial theory, it is believed this may prevent the immune system from forming the IgE antibodies that will later recognize the food and cause allergic reactions. When the child’s immune system is stronger, it may be able to tolerate the foods without becoming sensitized to them. Some physicians believe this technique shows more promise for the prevention of allergies in infants with a family history of allergies.

Individuals should learn what steps to take if they do come into contact with an allergen. Physicians often recommend that the most sensitive individuals carry a shot of epinephrine (a synthetic form of adrenaline that, when injected, opens breathing tubes and restores normal respiration quickly) to counteract the affects of the potentially life-threatening allergic reaction known as anaphylactic shock. These individuals should know how to correctly self-administer their medication.

Individuals with strong reactions should also carry a medical alert bracelet or necklace to inform healthcare workers of their condition.