Last year, after a dinner of mussels in garlic butter sauce, Maureen Chalmers, 56, woke up with her hands, feet, and lips swollen. 

Despite enjoying seafood for as long as she can remember—the Oxford, Conn. resident describes herself as a “typical New Englander”—Chalmers suspects that she might have a shellfish allergy. She’s now avoiding shellfish until she talks to her doctor at her next appointment. 

Her fears aren’t unfounded. A study published last week in the Journal of the American Medical Association reports that 10.8% of U.S. adults surveyed had at least one food allergy. That translates to more than 26 million adults.

Experts are hailing the study for its focus on adults with food allergies and for the breadth of the allergens included in the research.

Nearly half of the adults in the study had a food allergy that, like Chalmers’, began in adulthood. The study also reports that allergies to shellfish and finfish (salmon, cod, etc.) are more likely to develop in adults.

The study also noted who is more likely to get a food allergy: women, people of color, and people who also have asthma, eczema, allergic rhinitis, hives, or latex allergies.

This wasn’t Chalmers’ first encounter with a food allergy. She was diagnosed with a nut allergy in her 30s. And that experience isn’t unusual—the study found that 45.3% of adults with food allergies were allergic to multiple foods.

Not just for kids

“Food allergies used to be considered a childhood disease you could outgrow,” says Kenneth Mendez, president and CEO of the Asthma and Allergy Foundation of America. “It’s good to have this [study’s] data, because a lot of data historically collected has been focused on children.”

Along with its focus on adults, this study examines the spectrum of foods that can trigger allergies. Many previous studies have focused only on specific allergens. 

What is a food allergy?

This study separates true food allergies from food intolerances or sensitivities. That’s an important distinction.

People often self-diagnose intolerances and sensitivities as food allergies—you probably know someone who claims to be allergic to dairy or gluten. The study found that 19% of people believed they had a food allergy, while only 10.8% actually did. 

A gluten sensitivity is not the same thing as a wheat allergy, and lactose intolerance is not the same as a dairy allergy.

With food allergies, your body thinks it’s being invaded and launches an immune system response. These allergic reactions can be severe and sometimes (though rarely) cause life-threatening anaphylaxis, where the body releases a flood of chemicals that can cause a rapid drop in blood pressure, constriction of the throat or fainting.

Intolerances and sensitivities might stem from enzyme deficiencies or other causes. They often trigger gastrointestinal distress, headaches or joint pain, and fatigue. 

Worrisome signs

A gluten sensitivity is not the same thing as a wheat allergy, and dairy intolerance is not the same as a dairy allergy.

Food allergies can cause symptoms like hives, swelling, difficulty swallowing, throat or chest tightening, wheezing or trouble breathing, vomiting, chest pain, rapid heart rate, fainting, dizziness, lightheadedness, or low blood pressure. 

These allergies can be dangerous—more than half of people in the study had a severe reaction, and 38% needed emergency care for their symptoms. People over 50 were less likely to have a severe reaction compared to their younger peers. (The study’s participants were age 46.6, on average.)

Since it’s hard to know how severe a reaction to a food might be, adults with diagnosed food allergies should have a prescription for epinephrine, a drug that relaxes the muscles in the airway. 

Only about a quarter of people in the study had a current prescription, though, and those over 50 were much less likely to have epinephrine on hand.

Chalmers was prescribed epinephrine back in her 30s, but she concedes she doesn’t carry it anymore. Instead, she avoids foods with nuts and shellfish. 

Mendez would like to see epinephrine widely accessible in public spaces, the same way defibrillators are. 

Recognize the symptoms

Adults with diagnosed food allergies should have a prescription for epinephrine.

Many adults don’t recognize their symptoms as signs of a food allergy. If you notice symptoms, Mendez recommends keeping a journal and making an appointment with an allergist to help uncover the cause. 

Your doctor can diagnose your allergies, prescribe epinephrine, and counsel you on how to best manage your condition. 

Of course, with symptoms like swelling of the lips and tongue or trouble breathing you should seek medical help right away. 

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