Allergy to food is a reaction of the immune system that occurs soon after eating a certain food. Even a small amount of the food that causes allergies can trigger signs and symptoms such as digestive problems, hives and swollen airways. A food allergy can cause severe symptoms in some people, or even a life-threatening reaction known as anaphylaxis.
For people who have a food allergy, even exposure to very small amounts of the problem food can cause an allergic reaction.
It's easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.
An allergic reaction to a given food may be uncomfortable but not severe for some people. An allergic food reaction can be fearsome and even life-threatening for other people. Symptoms of food allergy usually develop within a couple of minutes to two hours of eating the offending food.
The most common food allergy signs and symptoms include:
Swelling of the tongue, mouth or face
Low blood pressure
A food allergy may in some people trigger a severe allergic reaction called anaphylaxis. This can cause life-threatening symptoms and signs including:
Constriction and airways tightening
A swollen throat, or a lump in your throat that makes it hard to breathe
Blood pressure shock with severe drop
Dizziness, loss of consciousness or lightheadedness
Emergency treatment is critical to anaphylaxis. Anaphylaxis untreated can cause a coma, or even death.
If you have a food allergy, your immune system mistakenly identifies a particular food or a substance in the food as harmful. In response, your immune system triggers cells to release an antibody known as immunoglobulin E ( IgE) to neutralize the food or food substance (the allergen) that causes allergies.
The next time you eat even the smallest amount of that food, IgE antibodies feel it and signal your immune system to release a chemical called histamine into your bloodstream, along with other chemicals. Allergy symptoms are caused by these chemicals.
In adults some proteins trigger the majority of food allergies in:
Shellfish like shrimp, lobster and crab
Tree nuts, for example walnuts and pecans
Food allergies in children are generally triggered by proteins in:
If you know you 're allergic to food follow these steps:
Know what you eat and you drink. Be sure to carefully read labels on foods.
If you've already had a severe reaction, wear a medical alert bracelet or necklace that lets others know you 're allergic to food in case you have a reaction and you can't communicate.
Talk to your doctor about prescribing Epinephrine for Emergency. If you are at risk of a severe allergic reaction, you may need to carry an epinephrine auto injector (Adrenaclick, EpiPen).
Watch out for restaurants. Be sure your server or chef is aware that you are absolutely unable to eat the food to which you are allergic, and you need to be absolutely sure that the meal you order does not contain it. Also, make sure that food is not prepared on surfaces or in pans containing any of the food to which you are allergic.
Don't be reluctant to convey your needs. Usually restaurant staff are more than happy to help when they understand your request clearly.
Plan out meals and snacks before you leave home. If necessary, when you're traveling or going to an event, take a cooler packed with allergen-free food. If you or your child can not have the cake or dessert at a party, bring a special treat that has been approved so no one feels left out of the celebration.