Think You Have an Allergy? Two to One You’re Wrong

Only 10 percent of adults have food allergies but twice that number think they do, huge new study shows, and yes, adult-onset allergy is a thing

Adults seem prone to developing seafood allergies
Ronen Malchan

You’d think you’d know if you have allergies. But guess what, it seems that a lot of people only think they have them.

One in five Americans are sure they have a food allergy, but the true rate is one in 10, report doctors at the Lurie Children’s Hospital of Chicago in the Journal of the American Medical Association, based on surveying over 40,000 adults.

Specifically, in that large group, 19 percent reported suffering from food allergy – but only 10.8 percent had “convincing food allergy prevalence,” the doctors wrote. Yes, only 10 percent of American adults have food allergy but twice that number think they do, says the lead author, Dr. Ruchi Gupta, MD, MPH.

Some people may really not react well to some given foods, but that doesn’t mean they’re allergic any more than burping after a soda is a sign of anaphylactic shock.

The doctors also found that among the truly allergic, nearly half (around 45 percent) were sensitive to multiple foods.

Gupta urges anybody who suspects they have an allergy to get tested, certainly before deciding to forgo a food. “If food allergy is confirmed, understanding the management is also critical – including recognizing symptoms of anaphylaxis and how and when to use epinephrine,” he points out.

Adult onset is a thing

The study also confirmed previous (unrelated) findings that a lot of people are developing allergies late in life. Nearly half the respondents (48 percent) in the present study developed at least one of their food allergies as an adult. So, the assumption that allergies develop in childhood, and we either get over them or don’t, is inaccurate.

Some allergic children can, in time, develop tolerance and happily eat the food unharmed. Conversely, adult-onset allergy can happen even in the case of foods previously tolerated. This seems to be likelier with seafood, for some reason, and seafood allergy (to shellfish and finny fish – the lot) is more common in areas that depend on the marine life for subsistence.

Sometimes, a child develops a food allergy and outgrows it, only to have it reappear in adulthood, the Mayo Clinic points out. Adult onset is very much a thing in Israel, it seems. Only about 2 percent of first-graders in Israel have diagnosed food allergies, the Health Ministry told Haaretz – but among adults the rate of allergies may be as high as 40 percent. (No such mass study like the American one has been done here yet.)

In 2016, some 450 Israeli kids were rushed from school to hospital because of allergic reaction to food, the ministry says. The ministry also notes that in Israel, in keeping with the global trend, allergy rates have been increasing.

People are not born with allergies, though there is some evidence that people can be born with propensity (meaning, the tendency may be inherited).

Allergy arises when our immune systems mistake a harmless substance – anything from cat fur to cashews to shrimp – as a threat. Our immune reaction releases chemicals that cause the allergy symptoms, which can happen within minutes or even hours.

Common symptoms include rash and itchy eyes or tongue; another is asthma. The World Health Organization reported about 300 million cases around the globe in 2014; it projects that figure reaching 400 million by the year 2025.

Asthma isn’t always associated with allergy. In Israel, though, among children 90 percent have asthma because of allergy. That ratio drops to 70 percent among adults, the Health Ministry says.

The ministry also notes that one doesn’t need to actually eat a food for the allergic reaction to begin, if one is sensitive. Just touching it or breathing the air with particles of the offending thing can be enough to trigger the reaction.

Sound far-fetched? If a kid rips open a bag of peanut puffs, minuscule particles can become airborne. If a person standing by is keenly sensitive to peanuts, their body will react. Sometimes even the smell of fish is enough to trigger anaphylactic shock.

The study data indicate that the most prevalent food allergens among American adults are shellfish (affecting 7.2 million adults), milk (4.7 million), peanuts (4.5 million), tree nuts (3 million), finny fish (2.2 million), eggs (2 million), wheat (2 million), soy (1.5 million) and sesame (half a million). The Israeli health authorities add oatmeal, barley and chestnuts to the list of common dangers.

For what it’s worth, some people are allergic to animal foods – but let’s not go there.