Common Food Allergy Triggers

Medically Reviewed by Nayana Ambardekar, MD on September 03, 2023
3 min read

Dip into hot salsa or spicy Indian food, and your nose starts running. Beans give you gas, or a glass of wine means a headache later. If you're lactose intolerant, you expect diarrhea when you eat cheese or milk.

Most people have reactions to foods like these from time to time. But they're usually food sensitivities or intolerances. They aren't caused by your immune system.

A food allergy is different. Your body mistakes harmless food as something that could make you sick. When you eat something you're allergic to, your immune system responds to protect you. 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 things cause about 90% of food allergy reactions:

  • Milk (mostly in children)
  • Eggs
  • Peanuts
  • Tree nuts, like walnuts, almonds, pine nuts, brazil nuts, and pecans
  • Soy
  • Wheat 
  • Fish (mostly in adults)
  • Shellfish (mostly in adults)

Almost any food can trigger an allergy, though. Less common ones include:

  • Corn
  • Gelatin
  • 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 (hives)
  • Runny or stuffy nose, sneezing, or a slight, dry cough
  • Itchy, watery, red eyes
  • Itchy mouth or inside your ear
  • Funny taste in your mouth
  • Upset stomach, cramps, throwing up, or diarrhea

Most often, peanuts, nuts, fish, and shellfish 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
  • 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) in case you have a reaction. It can ease symptoms until you can get medical attention. Do not hesitate to use the epinephrine auto-injector even if you are unsure your symptoms are caused by an allergy. The epinephrine will not hurt you and 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.

The key to controlling a food allergy? Avoid the problem food. That isn't always easy, though. It may be hidden as an ingredient in something else.

  • Most baked goods, like cakes and cookies, are made with eggs and sometimes nuts.
  • Water-packed tuna may have added nonfat dry milk.
  • Salad dressing could be made with soybean oil.
  • A hot dog may contain milk protein.

So, be sure to read food labels. That's a good place to start.

Still, labels don't always tell the whole story. For example, pineapple, milk casein, or hydrolyzed soy protein may be used in microwave popcorn -- yet you won't see them on the ingredient list. You'll see the catch-all terms "flavoring" or "natural flavoring" instead. Words like "emulsifier" or "binder" can signal soy or egg in the product.

When you have a food allergy, you need to get familiar with these general terms and what specific things they can include. If you have questions about any product, check with the manufacturer. The customer service department or the quality assurance officer should be able to help you figure out if the food is safe for you.

You'll need to read menus at restaurants carefully, too. Ask about how food is prepared before you order if you have any concerns.