What’s the difference between a food allergy and a food intolerance?

When you have a food allergy, your immune system can treat the food as a threat. You may have symptoms that include:

• Hives
• Swelling
• Trouble breathing
• Vomiting

If you have a severe food allergy, even a tiny amount can cause a serious reaction.

When you have a food intolerance, your body has trouble digesting that food. You won’t have a life-threatening reaction. You may have:  

• Bloating
• Gas
• Diarrhea
• Trouble moving your bowels (constipation)
• Stomach pain
• Headache
• A very tired feeling (fatigue)

If someone has a food allergy, what medicines should they keep on hand?

For severe reactions: Ask your doctor to prescribe an epinephrine auto-injector (brands include EpiPen and Auvi Q). It’s best to keep one nearby at all times.

Auto-injectors need to be replaced when they expire. You can find the expiration date on the packaging. Use an auto-injector as soon as you see signs of a severe allergic reaction.

For mild reactions: You can buy antihistamines over the counter to treat symptoms. Antihistamines include Allegra (fexofenadine), Benadryl (diphenhydramine), Claritin (loratadine) and Zyrtec (cetirizine).

What is anaphylaxis? What are signs of anaphylaxis?

Anaphylaxis is a severe allergic reaction. It might be life-threatening. Symptoms usually start within five to 30 minutes after eating a food you are allergic to.

Call 911 or go to an emergency room, and use an epinephrine auto-injector if you can, if you see these signs:

• Trouble breathing
• Swelling throat, tongue or lips
• Vomiting or diarrhea with a rash
• Fast heartbeat
• Feeling dizzy or passing out

My or my child’s eczema seems worse after eating some foods. Should we avoid them?

It depends. Eczema is a skin condition that causes redness, dryness and itching. It can return or get worse for many reasons.

Food allergies are an uncommon cause of eczema. Allergy tests don’t tell us which foods may make eczema worse.

If you or your child regularly eat a food without a serious allergic reaction, you can usually keep eating it.

Removing a food from a diet can lead to other concerns. Before you do this, please talk with your provider or your child's provider about elimination diets.

If someone has a peanut allergy, are they also allergic to tree nuts?

About 30% of people with peanut allergies are also allergic to tree nuts. If someone has a peanut allergy and shows no sign of a tree nut allergy, they can safely eat tree nuts.

Do people outgrow food allergies?

About 80% of children with egg, milk or wheat allergies outgrow them, usually by age 16.

Allergies to peanuts, tree nuts, seeds and seafood tend to be lifelong.

Can I develop food allergies as an adult?

Yes. Shellfish is the most common food adults become allergic to.

Some adults with pollen allergies develop Oral Allergy Syndrome, also called Pollen-Food Allergy Syndrome. They react to some nuts and fresh fruits and vegetables with proteins that mimic pollen proteins. Symptoms are usually mild. They include itchy mouth, lip and throat.

If I’m allergic to a food, do I have to keep it out of my home?

Not always. Severe allergic reactions usually happen only when you eat a food. You can have the food in your home if everyone is careful to avoid accidentally exposing you. Anyone who handles the food should wash their hands and wipe down surfaces.

Do food allergies and asthma affect each other?

People with food allergies may be more likely to develop severe asthma. People with asthma are more likely to have severe reactions to foods, especially if their asthma is not well-controlled.

Can allergy tests tell how severe an allergy is?

No. Allergy tests show which foods your body may react to. The tests don’t tell us how severe a reaction may be.

If a skin-prick test leads to a large, red bump on your skin, that means you’re more likely to react to that food.

What is the difference between a blood IgE test and a skin-prick test?

The tests are done differently. The waiting time for results is different.

IgE, or immunoglobulin E, is an antibody your immune system makes when it senses a threat.

Blood IgE tests detect IgE in the blood. We use a thin needle to draw blood from your arm. Results take a few days.

Skin-prick tests detect IgE in the skin. We make tiny scratches on your back or arm. We use small needles with tiny drops of a food or ingredient. You may feel itchy. Your skin will react by making bumps (wheals). We measure these to decide if your test is positive or negative. Results take about 15 minutes.

Your doctor can help you decide which tests are best.

If I have a negative skin-prick test, can I still have a food allergy?

Not usually.

Tests can have “false negative” or “false positive” results:

• A false negative means you have a food allergy but the test didn’t show it.
• A false positive means you don’t have a food allergy, but a test came back that you do.

Skin-prick tests rarely miss a food allergy. But about 50-60% may show that you have one when you don’t. That's why we discuss your health history with you and test only when you have a history of reacting to a specific food.

How often should we get allergy tests?

Many patients have tests once a year. If a child has a food allergy they are unlikely to outgrow, they may have tests every two years.

Is there a cure for food allergies?

Not yet. It’s best to:

• Avoid any food that causes a reaction.
• Keep an epinephrine auto-injector (like an EpiPen) nearby to treat severe reactions.

Can you get shots for food allergies?

Not until recently. In studies, some people who got shots for food allergies had severe reactions.

In February 2024, the U.S. Food and Drug Administration approved a medication called omalizumab (Xolair) to treat food allergies in children ages 1 or older. It is given as a shot.

Xolair is not a cure. It helps protect you from a severe reaction if you accidentally eat a food or ingredient you’re allergic to.

Can I desensitize my child by rubbing a food on their skin?

No. Smearing or rubbing food on a child’s skin may increase the risk of becoming allergic to the food.