The start of food allergies in adulthood is not common and is

surprising given the prevalence of allergies emerging in

childhood. A large survey (Food Allergy and Education FARE) of

40,0000. adults in 2015-2016 found that 1 out of 10 adults has a

food allergy. Half of these allergies began in adulthood. The

most common adult onset food allergy was shellfish, followed

by milk and peanut making the top three allergies. The survey

provides excellent adult allergy information. Further research

will be needed to understand the cause of adult onset allergies.

Logo for WebMD

Adult-Onset Food Allergies Increasing, Confusing

By Jennifer Clopton

allergy info on food label


Jan. 14, 2019 — Martin Malawer, MD, had environmental allergies as a child but never had any reaction to food until he was about 30,000 feet in the air on a plane to France.

“About two-thirds of the way over the Atlantic, I had shrimp cocktail in business class. I had that a million times with no problem, but all of a sudden one eye started swelling up,” he says. “About half an hour later, my other eye started swelling up. It got very bad. I could hardly see out of them, and then I started getting short of breath,” Malawer, an oncology surgeon, recalls of that flight more than 30 years ago.SLIDESHOW

Slideshow: Food Allergy Triggers, Common and Uncommon

Close up of peanuts
1/21PeanutsThey’re in lots of products, including baked goods and sauces. Always check the food label. Packages must say if they have peanuts. When you eat out, ask how the food is prepared and let servers know you’re allergic. You should also avoid tree nuts, like walnuts or almonds, if they bother you.
Assortment of dairy foods
2/21Dairy FoodsMilk is one of the most common food allergy triggers for kids. Most outgrow it. In the meantime, your baby may need hypoallergenic or soy formula. Look at the label on packaged foods. Even things like tuna can have milk protein in it. Sometimes it shows up as the ingredient casein.
Assortment of egg based foods
3/21EggsIt’s not just a problem with omelettes. Eggs are in many foods, including noodles, mayonnaise, and baked goods. They can also be in some surprising places, like the foam topping on drinks or the egg wash on pretzels. They’re used to make most flu vaccines, too, so check with your doctor before you get it.
Assortment of shellfish
4/21ShellfishYou can get a sudden seafood allergy as an adult. If you do, it’ll typically stick with you for life. Shrimp, crab, crawfish, and lobster can all cause serious reactions. Clams, mussels, scallops, escargot, octopuses, and squid can be triggers, too. If you’re allergic, avoid all shellfish.
Food label with nut allergy warning
5/21Tree NutsThey can even be in lotions made from tree nut oils, like shea oil. Packaged foods must list them. But they’re harder to avoid in restaurants and bakeries. If you’re allergic, watch out for walnuts, almonds, pecans, hazelnuts, cashews, pistachios, Brazil nuts, and pine nuts. Nutmeg, water chestnuts, sunflower seeds, and sesame seeds aren’t nuts and should be OK.
Fresh fish on display
6/21FishSome people are allergic to fresh salmon, tuna, or halibut. If you’re allergic to one type of fish, you may react to others, too. Be careful of the fish sauce in Thai and Chinese food. The same goes for Caesar dressing and Worcestershire sauce, which often have anchovies in them.
Assortment of soy based foods
7/21SoyBreads, cookies, canned soups, processed meats, and snack foods all can have soy in them. If you’re allergic, read food labels so you can steer clear. Also avoid the traditional soy foods: edamame, tofu, soy milk, miso, and soy sauce. Babies and children are more likely to have this allergy than adults.
Assortment of breads
8/21WheatIt’s in a lot of things, from bread to beer, and salad dressing to deli meats. Why? Wheat proteins help some processed foods stick together and give them texture. If you’re allergic to wheat, other grains — like barley, oats, rye, corn, and rice — may be safe. But you may need to avoid bulgur, couscous, and farina. It’s possible to have a wheat allergy but be OK to eat gluten.
Selection of gluten free food products
9/21Gluten Sensitivity?You can be sensitive to something but not allergic. Gluten is usually found in wheat, rye, and barley. If you’re allergic, your immune system reacts to any food that has it. And it can cause permanent damage to your intestines when you have Celiac disease. You may also find that gluten upsets your digestive system, without Celiac disease or an allergy. It doesn’t cause permanent damage, but you may want to avoid it. 
Illustration of blood with antibodies
10/21How a Food Allergy StartsYou eat or drink a trigger food and your immune system kicks into gear. You won’t notice any allergy symptoms like a rash or itching this first time, but your body will watch out for that item again. The next time you eat it, since your body thinks the food is bad, it’ll release the chemical histamine, which causes allergy symptoms such as rashes, itching, and swelling.
Skin rash from food allergy reaction
11/21Know the SymptomsIf you eat something you’re allergic to, your symptoms will probably start pretty quickly. It could take just a few minutes to 2 hours. You could have: Hives or another skin rashTingling or itching in your mouthSwelling of your face, tongue, or lipsCoughing or wheezingVomiting, diarrhea, or belly crampsSwelling of throat and vocal cordsTrouble breathing
Anaphylaxis injection
12/21The Riskiest ReactionSymptoms can sometimes be life-threatening. This is called anaphylaxis. When this happens, you may have trouble breathing and your blood pressure may drop. If you have food allergies, your doctor might prescribe epinephrine shots to always carry with you. If you have food allergies, your doctor might prescribe epinephrine shots to always carry with you. Call 911 and give yourself a shot at the first sign of symptoms. Children with a severe peanut allergy may also be prescribed the newly approved drug Palforzia to help lesson symptoms.
Half eaten shrimp dinner
13/21You Can’t Always Predict ItOne bite of seafood went down OK last time. Does that mean that much is fine for you? Not necessarily, if you’re allergic. In general, the size of your allergic reaction you’ll have depends on how bad the allergy is and how much of the trigger food you eat. But reactions can surprise you. Yours could be more severe next time.
Sign indicating restroom location
14/21Intolerance or Allergy?Even if you have trouble digesting something, like milk or gluten, it may not be an allergy. Your body may not handle that food well, and have bloating, cramps, and diarrhea. But if it doesn’t involve your immune system, it’s not an allergy.  For instance, lactose intolerance happens when your body can’t break down lactose, the sugar in milk and dairy products.
MSG added to food
15/21What About Food Additives?You can have a reaction to them without being allergic. MSG (monosodium glutamate) can cause flushing, warmth, headache, and chest discomfort. Sulfites, which are found in some dried fruits, wine, and other foods, can cause breathing problems for people with asthma. Food labels must list sulfites.
Raw fresh vegetables
16/21What Is Oral Allergy Syndrome?Some people who have hay fever, especially triggered by birch or ragweed pollen, react to uncooked apples, cherries, kiwis, celery, tomatoes, and green peppers. They feel tingling, itching, or swelling of the lips, tongue, or throat. And they can get watery or itchy eyes, and a runny, sneezy nose.
Athlete suffering from food allergy
17/21When Exercise Triggers ItThis problem happens only in some people when they eat something they’re allergic to right before they exercise. Their body temperature rises and the food can cause an allergic reaction, such as itching, hives, lightheadedness, or even anaphylaxis. The items most likely to trigger this type of allergy are shellfish, alcohol, tomatoes, cheese, and celery. Avoid your trigger foods for a couple of hours before you exercise.
Entries in a food allergy diary
18/21Should You Try an Elimination Diet?If you’re not sure what caused an allergic reaction, write down what you eat and how you feel. It can show possible triggers. Or ask your doctor about going on an elimination diet. On this plan, you stop eating one suspicious food at a time. This may help you figure out which food causes your allergy.
skin prick test
19/21How to Tell for SureYou may need tests to find out if you have a food allergy.Skin prick test — This is the most common one. An allergist puts a drop of liquid on your skin, then pricks the skin to allow it to soak in. No reaction means you’re not allergic.Blood test — Your doctor takes a sample of your blood to see if it reacts to certain triggers.Supervised food challenge — While a doctor watches, you eat foods to see if you react.
High school students eating lunch
20/21Will Your Child Outgrow It?Kids are likely to outgrow allergies to milk, eggs, wheat, and soy. But children with peanut, tree nut, fish, and shellfish allergies usually have them for life. If you want to see whether your kid has outgrown her allergy, your doctor can do a blood test. Do not feed your child a possible trigger food on your own to check. Even a small amount could cause a life-threatening reaction.
Little girl with food allergy alert bracelet
21/21Tips to Manage Your Food AllergyYou’ll need to avoid your trigger foods and read labels to check ingredients. Make a plan for what you need to do if you or your child accidentally eats something off-limits. At the first sign of anaphylaxis, (wheezing, trouble breathing, dizziness) call 911 and use an epinephrine shot. Give yourself another shot if your symptoms don’t get better. It’s wise to wear a medical ID bracelet, or carry something that says you have the allergy.

Reviewed by Melinda Ratini on 2/18/2020

With his medical training, he immediately knew he was having an allergic reaction, but the flight crew didn’t have any epinephrine in their first aid kit. So the flight attendants gave him antihistamines.

“By the time we landed in Paris, I couldn’t see out of my eyes, they were so swollen,” says Malawer, who got treatment and recovered once he was on the ground. When he returned home to the United States, he went to an allergist and discovered he had gotten an allergy to shrimp at the age of 40. More than 30 years later, he still has it, something he knows because he’s accidentally come in contact with shrimp a few times through the years.

“One day when I was working at the hospital, I ate some soup and didn’t realize there was shrimp in it. The same reaction started happening again, so a nurse ran and got epinephrine and gave it to me, and it stopped,” he explains.

Malawer is part of the more than 10% of adults in the United States — more than 26 million — now estimated to have a food allergy, according to a new study published this month in JAMA Network Open. Ruchi Gupta, MD, a pediatrician at Lurie Children’s Hospital in Chicago, led the team.

“We think of food allergies happening in children, and they do, at a rate of about 1 in 13. But I don’t think the U.S. has really talked about how often this happens in adults. Adult food allergies impact one in 10, and half of these are food allergies starting in adulthood,” says Gupta, who’s also a professor of pediatrics at Northwestern University’s Feinberg School of Medicine.

Allergy Statistics

There are a lot of data about food allergies in children, but until now, there hasn’t been much research done on how often food allergies appear after someone is an adult.

“Prevalence studies such as this one are much needed to help us further define the scope of the food allergy epidemic in the U.S.,” says Lisa Gable, CEO of Food Allergy Research & Education (FARE), the largest nonprofit dedicated to food allergy awareness, education, and research .

The new data come from a 2015-2016 survey of more than 40,000 adults across the country, and Gupta says it is one of the first to assess the general population for specific food allergy types and symptoms. The results show:

  • One in 10 adults have a food allergy.
  • More than half (51.1%) have had a severe reaction.
  • Almost four in 10 (38.3%) report at least one reaction that required emergency care.
  • But only one in 20 with a convincing food allergy have a doctor-confirmed diagnosis.
  • And less than a quarter (24%) with a food allergy report a current epinephrine prescription.

Given the rise of allergies in children, Gupta says, it makes sense that more adults have allergies, because those children are growing up. But she says that doesn’t entirely account for the prevalence of food allergies among adults. Her research finds:

  • 48% of the adult population with a convincing food allergy reported getting at least one as an adult. (They may have had others as a child.)
  • But one out of 4 adults with a food allergy reported getting their first allergy in adulthood.

“This study signals that food allergy among adults is a more significant issue in the U.S. than previously thought, particularly the emerging health problem of adults developing their food allergies later in life, even after regularly eating foods that were previously harmless,” Gable says.

“We were surprised that adult-onset food allergies were so common,” Gupta says. “More research is needed to understand why this is occurring and how we might prevent it.”

Researchers also discovered that nearly one in five, or 19%, of adults think they have a food allergy, but researchers say the symptoms they reported may actually be consistent with other food-related conditions. Gupta says negative reactions to food are common and can be confusing, with some being treatable and others life-threatening. Possible causes outside of a true food allergy may include intolerances, sensitivities, oral allergy syndrome, and many others.

What Adult Reactions Look Like

When it comes to types of food allergies, Gupta’s study finds shellfish is the top food allergen in adults, affecting 7.2 million of them.

Food Allergies and Food Intolerance

WebMD provides an overview of food allergies and intolerances, their symptoms, causes, diagnosis and treatments.ABOUT

Shellfish allergy commonly begins in adulthood, is rarely outgrown, and therefore impacts the lifespan,” she explains.

Jodi Duke has experienced that. She got an allergy to shellfish in her 30s after having her second child. Until then, she ate crab often and loved it. But during her last visit to a crab house, she took a bite and suddenly realized something had changed.

“I began to feel hot and dizzy. The next thing I remember was waking up on the floor. I had passed out and ended up in an ambulance headed to the emergency room. After several tests, the doctors explained that everything looked good on the tests and I should consult an allergy specialist,” Duke explains. “When I did, I found out I had developed a shellfish allergy and am now unable to eat any type of shellfish. I am lucky that my allergy is the type that I have to actually eat the shellfish to have a reaction, but I do still have to be careful.”

Gupta’s study found rates of all allergies, no matter when they started, were high in adults for a variety of other foods too, including:

  • Milk (4.7 million people)
  • Peanut (4.5 million people)
  • Tree nut (3 million people)
  • Fin fish (2.2 million people)
  • Egg (2 million people)
  • Wheat (2 million people)
  • Soy (1.5 million people)
  • Sesame (0.5 million people).

As for causes, little is known for sure, but Gupta says her team is looking at data to explore that. She says they are focusing on hormone changes, like pregnancy, as well as genetic and environmental triggers, like a change in location or possible viral and bacterial causes.

“Understanding potential triggers for new allergies is essential as we are seeing more adult-onset food allergy, and significantly more in women than men. We need to examine the why,” Gupta says.

Managing Food Allergies

FARE, the allergy nonprofit, says a food allergy reaction sends someone to an emergency room in the United States every 3 minutes. The group warns that symptoms can appear within minutes or hours after eating a food, and reactions can affect skin (hives), the gastrointestinal tract (vomiting or diarrhea), or your respiratory or cardiovascular system. Reactions are also very unpredictable. They can vary between people, from mild to severe and anaphylactic (a reaction that could be life-threatening), and the same person may not react the same twice.

Allergy experts say the potential severity of reactions, paired with the rise in allergies, points to the need for clear information on ingredients, so many hope those in the food industry are paying attention to this new data.

“If one in 10 people who enter your restaurant could exit in an ambulance if you make a mistake, you better not ignore what people are telling you,” says Scott H. Sicherer, MD, director of the Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai in New York City. “These numbers mean industries have to be careful with labeling. Restaurants have to be careful with serving, and physicians need to make sure to educate adults who might not watch out for themselves as much as their children. This is not something to minimize. It’s the opposite. A lot of people have significant allergies, and we have to take this seriously.”

Allergy experts say the other message that people should take from this study is to see a doctor if you have a reaction to food. Many, like Erin Malawer, the author of the food allergy awareness blog Allergy Shmallergy, are concerned how many appear to be trying to handle food reactions without proper guidance or emergency medicine.

“Patients with food allergies, both children and adults, uniquely rely on others to keep them safe. This means they need other people to have a general level of understanding about food allergies. It appears that even those suffering symptoms don’t have the information they need to manage their own condition properly,” she explains.

Doctors and advocates agree that a proper diagnosis is critical.

“It is important to get a diagnosis so you know how to manage it daily,” Gupta says.

“Self-diagnosis can limit your diet unnecessarily and may prevent you from receiving appropriate care, including epinephrine auto-injectors that can save your life in the event of a severe food allergy reaction,” Gable says.

Katie James can speak to the fact that a proper diagnosis can be life-changing. She says she thought she had food allergies because in her mid-20s, she had nausea, bloating, gas, stomach cramps, and diarrhea after meals. “It wasn’t consistent enough to pinpoint the culprit, but I was convinced I had to be allergic to something. My symptoms were severe, and I would feel sick for about 24 hours,” she says.

She went to an allergist for testing, which showed she had no food allergies, so the allergist suggested she document everything she ate for a week to see if patterns emerged. They quickly did.

“I kept my journal for about a week, and then my diagnosis became obvious: I was lactose intolerant. My doctor recommended lactase pills, and sure enough, I was able to ingest milk, ice cream, decadent cream pasta, and of course, pizza,” James says. “It was such a simple ‘cure’ to such a debilitating problem.”WebMD Health News Reviewed by Brunilda Nazario, MD on January 11, 2019