UNC Health Care
Illustration of shelled peanuts floating in a blue sky with clouds.

Can Simply Smelling Peanuts Cause an Allergic Reaction?

A UNC allergist addresses the risk of airborne peanut allergies.

Your carry-on bag is safely stowed overhead, your little one is buckled in and playing with her favorite toy, and you’re ready to dive into the thriller you brought to read on your flight when you smell it. Peanuts. You begin to panic. Her EpiPen is somewhere in the carry-on above, but the “fasten seat belt” sign is glaring at you. What should you do?

Take a deep breath and relax. Even if you are allergic to peanuts, touching, smelling or inhaling particles from peanuts cannot cause an allergic reaction—at least not the serious, life-threatening type that everyone with a peanut allergy fears. You are not in danger unless you eat them.

What It Means to Be Allergic to Peanuts

When you’re allergic to peanuts, you’re actually allergic to the proteins found in peanuts. Antibodies in your immune system float around waiting to jump into action if they come into contact with these proteins. This occurs when you eat a peanut—even a miniscule amount.

“When you have someone who’s allergic and ingests peanuts, the antibodies in the person’s immune system find and grab onto this peanut and cause your body to release certain chemicals, the most important of which is histamine,” says Edwin Kim, MD, director of the UNC Food Allergy Initiative.

Histamine can cause symptoms ranging from itching and hives to a severe, life-threatening reaction known as anaphylaxis. Anaphylaxis must be treated with epinephrine, which comes in an injectable pen, often called an EpiPen, followed by an emergency medical evaluation.

Smelling Peanuts Is Not the Same as Ingesting Them

While it is possible to breathe in a little bit of food protein, such as a peanut protein, that exposure is not enough to trigger a severe allergic reaction.

“The way I try to visualize it is it comes down to a threshold amount,” Dr. Kim says. “In order to get enough of an exposure to trigger a big reaction, it really takes ingestion. It is very, very, very, very rare for someone to just inhale it and then actually have an all-out anaphylactic attack.”

And while this idea holds for both peanuts and tree nuts, it’s important for people who are allergic to seafood to be aware: Reactions without ingestion do occasionally occur, Dr. Kim says. But the circumstances have to be just right; simply sitting next to someone eating shellfish, for example, won’t be a problem.

“There are reports where patients who are allergic to shellfish may be exposed to a steaming pot, perhaps at a clambake, and develop hives or asthma symptoms,” Dr. Kim says. “This is not (from) being in the same room as someone eating shrimp, but from directly breathing in the steam as it’s being cooked or boiled.”

When Exposure to Peanuts Can Cause a Physical Reaction

While just smelling peanuts won’t cause a severe reaction, if you’re allergic to peanuts, the smell can trigger a response in your body because it senses danger.

“Peanuts have a very potent smell. The smell may be enough to trigger some of the anxiety, concerns and fear that rightfully come because you anticipate a reaction,” Dr. Kim says. “It’s a survival instinct. Your body knows there is something around that it should not be eating.”

Dr. Kim says that if you are allergic to peanuts, you can experience nausea or just feel a little off if you smell them. “And if the person who sat in an airplane seat before you happened to eat peanuts and was not very clean, you could potentially touch it in a chair and have a little bit of a rash or irritation” on the skin, he says.

So whether it’s on a plane or at the lunchroom table, wipe down the area if you smell peanuts or are concerned about residue. Also, if you have a child who is allergic to peanuts, make sure you teach him or her early not to share food with friends.

“If they’re too young to know not to share foods, then that might be the one time where an actual separated table (for children with peanut allergies) could make sense,” Dr. Kim says. “But as they get older and you feel like they have learned this and can control their instincts, there’s no reason they can’t sit alongside their friends.”


Talk to your or your child’s doctor if you’re concerned about food allergies. If you need a doctor, find one near you.