More than 800,000 of these adults – more than 17% – developed their allergy after turning 18, according to a study published Tuesday in The Journal of Allergy and Clinical Immunology.
Peanut allergy is generally considered to be a pediatric problem, but more adults than children have allergies, said study author Dr. Ruchi Gupta, director of the Northwestern University’s Illinois Center for Food Allergy and Asthma Research. But only 15% to 20% of children with peanut allergy will overcome their allergy in adulthood, according to the study.
Adults who reported developing a peanut allergy in adulthood were significantly less likely to be diagnosed by a doctor compared to adults who reported developing the allergy as children, according to a survey of more than 40,000 American adults.
Gupta said he realized that adults who have a negative reaction to a particular food tend to avoid eating it instead of having an allergy test. When you are diagnosed with peanut allergy, you receive confirmation that you are allergic, which affects how you live your life, she said.
Of the 2.9% of American adults who reported having a peanut allergy, only 1.8% – that is, 4.6 million people – had a convincing peanut allergy, according to the study.
Convincing symptoms include vomiting, hives and difficulty breathing, among others, said study author Christopher Warren, research consultant at the Food Allergy and Asthma Research Center. Some examples of symptoms that were not convincing include bloating and diarrhea, he said.
Self-diagnosed adults are also potentially placing an unnecessary burden on themselves from avoiding peanuts when they don’t need to, Warren added.
“They may be living their lives as if their next bite could lead to a very bad result, when it is something that would be so easy to avoid” through routine allergy tests, Warren said.
Another reason it is important to be diagnosed is because doctors can prescribe epinephrine, said Gupta, who is an emergency treatment for anaphylaxis, a severe reaction to an allergen.
Only 44% of adults with adult-onset peanut allergy reported having a prescription for epinephrine, compared with 56% of adults with childhood-onset peanut allergy, according to the study.
There is no known reason for the development of peanut allergies in adults, but a person’s environment or hormones may play a role, said Gupta. She said research was being done to see if a change in a person’s living environment or a fluctuation in women’s hormones when they entered puberty or menopause could cause an allergy.
What to do if you suspect an allergy
This study revealed that adult peanut allergies are much more prevalent than anticipated, said Steve Danon, senior vice president and head of public relations and communications for Food Allergy Research & Education, who was not involved in the study.
If you suspect you are allergic to peanuts, Danon recommended that you see your doctor for testing.
In addition to peanuts, he says you should be tested for other common allergens, such as nuts. Adults with adult-onset peanut allergy were more likely to report multiple allergies compared to adults with childhood-onset peanut allergies, according to the study.
The Food and Drug Administration has not approved any peanut allergy therapy for adults, Warren said, but there is therapy for children ages 4 to 17. The therapy slowly desensitizes children to peanuts, allowing them to ingest peanut protein and a milder or no reaction, according to the study.
Another benefit of being diagnosed as an adult is that you can participate in therapy tests for peanut allergy, Warren said. Clinical trials are an important part of the approval process for peanut allergy therapies for adults, he said.