Food allergies are caused by your immune system. Your body misidentifies a harmless food as something that could make you sick and tries to protect you. When you eat something you’re allergic to, your immune system responds. You might get a mild skin rash or itchy eyes, or you could have a bigger reaction that leaves you gasping for breath. Food allergies can be serious, but you can take steps to manage them. One of the best things you can do is avoid your trigger foods.
Eight foods cause about 90% of food allergy reactions:
- Milk (mostly in children)
- Tree nuts, like walnuts, almonds, pine nuts, brazil nuts, and pecans
- Wheat and other grains with gluten, including barley, rye, and oats
- Fish (mostly in adults)
- Shellfish (mostly in adults)
Less common foods that may trigger allergies include:
- Meat — beef, chicken, mutton, and pork
- Seeds, often sesame, sunflower, and poppy
- Spices, such as caraway, coriander, garlic, and mustard
An allergic reaction can happen within minutes of eating, or it may happen hours later.
Mild symptoms can be hard to tie to specific foods. You could get red, swollen, dry, or itchy skin rash, including hives or eczema. Or, you may experience a runny or stuffy nose, sneezing, or a slight, dry cough. Other symptoms can include itchy, watery, red eyes, itchy mouth or inside your ears, a funny taste in your mouth, or upset stomach, cramps, throwing up, or diarrhea.
Peanuts, nuts, fish, and shellfish more often cause severe reactions, although any food can. Symptoms include trouble breathing or swallowing, swollen lips, tongue, or throat, feeling weak, confused, or light-headed, or passing out, or experiencing chest pain or a weak, uneven heartbeat.
Because young children may not know how to describe what’s happening, they might say something like, “My mouth is tingling,” “My tongue feels heavy,” or “I’ve got a frog in my throat.” A hoarse or squeaky voice or slurring words are also signs of an allergic reaction in kids.
Sometimes symptoms affect your whole body and are so serious that they’re life-threatening. This kind of reaction is called anaphylaxis, and it’s a medical emergency. It usually happens a few minutes after you’ve eaten. If you have asthma as well as a food allergy, you’re more likely to have anaphylaxis. When you have a severe food allergy, you should carry injectable epinephrine (adrenaline). It can ease symptoms until you can get medical attention. Do not hesitate to use the epinephrine auto-injector ever if you are unsure your symptoms are caused by an allergy. The epinephrine could save your life.
For highly allergic people, even tiny amounts of a food (for example, 1/44,000 of a peanut kernel) can set off a reaction. Less sensitive people may be able to eat small amounts of their trigger food.