Can Adults Develop Food Allergies Later in Life?
Medically reviewed by the medical team at Allergy & Asthma Clinic of Maryland
Key Points
- Food allergies are not only a childhood condition, and many adults develop a new food allergy after age 18.
- Shellfish is the most common food allergy in U.S. adults, followed by milk, peanut, and tree nuts.
- A food allergy involves the immune system and can cause a severe reaction, while a food intolerance usually causes digestive discomfort.
- An allergist can confirm which foods are truly causing symptoms through a detailed history and targeted testing.
- Allergy & Asthma Clinic of Maryland in Silver Spring offers food allergy testing, diagnosis, and emergency preparedness planning for adults and children.
Many people assume food allergies start in childhood. So when an adult who has eaten shrimp for decades suddenly breaks out in hives after a seafood dinner, or notices an itchy mouth after biting into an apple, it can be confusing and frightening.
The truth is that adult food allergies are common and can develop at any age. National research has found that a large share of adults with food allergies developed at least one of them as adults. Knowing what to watch for, and when to get evaluated, can help you stay safe and avoid cutting foods out of your diet when you do not need to.
How Common Are Food Allergies in Adults?
Food allergies in adults are more common than most people realize. A national survey published in JAMA Network Open estimated that more than 10 percent of U.S. adults have a food allergy, and nearly half of them developed at least one food allergy in adulthood.
The same research found that many more adults believe they have a food allergy than actually do, and only about half of adults with convincing symptoms had a diagnosis confirmed by a physician. That gap matters. Some people avoid foods they do not need to avoid, while others with a real allergy go without a plan for handling a serious reaction.
The Most Common Adult-Onset Food Allergies
Any food can cause an allergic reaction, but a small group of foods is responsible for most of them. In adults, the most frequently reported food allergies include:
- Shellfish, such as shrimp, crab, and lobster, which is the most common food allergy among U.S. adults
- Milk
- Peanut
- Tree nuts, such as almonds, cashews, and walnuts
- Fin fish, such as salmon, tuna, and cod
- Egg, wheat, soy, and sesame
Shellfish allergy is a classic example of an allergy that often appears in adulthood, sometimes in people who ate shellfish without any trouble for years.
Why Do Food Allergies Develop in Adulthood?
Researchers do not yet fully understand why some people develop a food allergy later in life. A food allergy happens when the immune system mistakenly treats a protein in a food as harmful and produces allergic antibodies against it. The next time that food is eaten, the immune system reacts.
A few patterns are especially worth knowing about in adults:
Pollen Food Allergy Syndrome
Some people with seasonal pollen allergies notice an itchy or tingling mouth, lips, or throat after eating certain raw fruits, vegetables, or nuts. This happens because the proteins in those foods resemble pollen proteins. Symptoms are usually mild and limited to the mouth, and cooking the food often prevents the reaction. Because so many Maryland residents have tree, grass, or ragweed pollen allergies, this is a common reason adults first notice a reaction to food.
Alpha-Gal Syndrome
Alpha-gal syndrome is an allergy to a sugar molecule found in red meat, such as beef, pork, and lamb, and in some other mammal products. It has been linked to tick bites, particularly from the lone star tick, which is found in Maryland and much of the eastern United States. Unlike most food allergies, reactions are often delayed by several hours after eating, which can make the cause hard to recognize.
Reactions Tied to Exercise or Other Factors
In some adults, a food only causes a reaction when it is combined with another factor, such as exercising soon after eating, drinking alcohol, or taking certain pain relievers. These cases can be difficult to sort out without careful evaluation.
Food Allergy vs. Food Intolerance
Not every bad reaction to food is an allergy. A food intolerance, such as lactose intolerance, happens when the body has trouble digesting a food. It can cause bloating, gas, cramping, or diarrhea, and while it can be uncomfortable, it does not involve the immune system and is not life-threatening.
A true food allergy is different. Because it involves the immune system, even a small amount of the food can trigger symptoms, and reactions can affect the skin, breathing, digestion, and circulation all at once. Telling the two apart is important, because it determines whether you need emergency medication and how strictly you need to avoid a food.
Symptoms of a Food Allergy in Adults
Food allergy symptoms usually start within minutes to a couple of hours after eating. They can include:
- Hives, itching, or flushed skin
- Swelling of the lips, tongue, face, or throat
- Itching or tingling in the mouth
- Nausea, vomiting, stomach pain, or diarrhea
- Nasal congestion, sneezing, or coughing
- Wheezing, shortness of breath, or throat tightness
- Dizziness, lightheadedness, or fainting
A severe, whole-body reaction is called anaphylaxis. Signs include trouble breathing, throat tightness, a drop in blood pressure, or symptoms affecting more than one part of the body at once. Anaphylaxis is a medical emergency. If you have been prescribed an epinephrine auto-injector, use it right away and call 911.
How an Allergist Diagnoses Food Allergies
Diagnosing a food allergy starts with your story. An allergist will ask what you ate, how much, how soon symptoms started, what they looked like, and whether anything else, such as exercise or medication, was involved. These details guide which tests make sense.
Testing may include:
- Skin prick testing, in which a tiny amount of a food extract is placed on the skin to check for a reaction
- Blood testing, which measures allergic antibodies to specific foods
- An oral food challenge, in which the food is eaten in carefully measured, increasing amounts under medical supervision
Guidelines sponsored by the National Institute of Allergy and Infectious Diseases describe the supervised oral food challenge as an important tool for confirming or ruling out a food allergy. Skin and blood tests can show sensitization, but a positive result on its own does not always mean a person will react to the food. That is why test results are always interpreted alongside your history, and why at-home or online food sensitivity tests are not a substitute for an evaluation with an allergist.
Living With a Food Allergy as an Adult
Once a food allergy is confirmed, the goal is to keep you safe while keeping daily life as normal as possible. A personalized management plan often includes:
- Clear guidance on which foods to avoid and which related foods are likely safe
- An epinephrine auto-injector prescription, along with training on when and how to use it
- A written emergency action plan you can share with family, friends, and coworkers
- Tips for dining out, traveling, and attending events
Reading labels is a big part of avoidance. Under federal law, packaged foods must clearly identify the major food allergens, and sesame became the ninth major food allergen in 2023. Restaurant meals and foods prepared by others are not labeled the same way, so it is important to ask questions and let staff know about your allergy.
Your allergist can talk with you about whether any treatment approaches beyond avoidance and emergency preparedness may fit your situation.
Food Allergy Testing for Adults in Silver Spring, Maryland
If you have had a reaction to a food you used to eat without a problem, or you are avoiding foods without knowing whether you really need to, Allergy & Asthma Clinic of Maryland can help you get answers. Board-certified allergist and immunologist Vasif Kalfa, MD, has a particular interest in food allergies and provides testing, diagnosis, and emergency preparedness planning for adults and children.
Our office is located at 8630 Fenton Street, Suite 522, Silver Spring, MD 20910, and is open Monday through Friday from 8:30 am to 5:00 pm. To schedule, call (240) 531-2902 or book an appointment online. Insurance coverage varies by plan, so please contact our office or visit our Insurance & Fees page to confirm your coverage before your visit.
Frequently Asked Questions About Food Allergies in Adults
Can you suddenly develop a food allergy as an adult?
Yes. Food allergies can develop at any age, including in people who have eaten a food for years without a problem. Shellfish is one of the most common allergies to appear in adulthood.
What is the most common food allergy in adults?
Shellfish is the most common food allergy among adults in the United States. Milk, peanut, tree nuts, and fin fish are also common.
How can I tell if I have a food allergy or a food intolerance?
Food intolerances usually cause digestive symptoms such as bloating, gas, or diarrhea. Food allergies involve the immune system and can cause hives, swelling, wheezing, or a severe reaction called anaphylaxis. An allergist can help you sort out which one you are dealing with.
Why does my mouth itch when I eat raw fruit?
This is often caused by pollen food allergy syndrome, which affects some people with seasonal pollen allergies. Proteins in certain raw fruits, vegetables, and nuts resemble pollen proteins, causing itching or tingling in the mouth. Cooking the food often prevents the reaction.
Can a tick bite cause a red meat allergy?
Yes. Alpha-gal syndrome is an allergy to red meat and some other mammal products that has been linked to tick bites, especially from the lone star tick. Reactions are often delayed by several hours after eating.
Are at-home food sensitivity tests accurate?
At-home and online food sensitivity tests are not a reliable way to diagnose a food allergy. Accurate diagnosis depends on a detailed medical history combined with appropriate testing, which an allergist can provide.
Can adult-onset food allergies go away?
Some childhood food allergies are outgrown, but food allergies that begin in adulthood are more likely to persist. An allergist can monitor your allergy over time and let you know if retesting makes sense.
When should I see an allergist about a food reaction?
See an allergist if you have had hives, swelling, breathing trouble, or other symptoms after eating, or if you are avoiding foods without a confirmed diagnosis. If you ever have trouble breathing or throat tightness after eating, call 911.
Frequently Asked Questions About Allergy & Asthma Clinic of Maryland
Does Allergy & Asthma Clinic of Maryland treat adults with food allergies?
Yes. The practice provides food allergy testing, diagnosis, avoidance strategies, and emergency preparedness planning for adults as well as children.
Where is Allergy & Asthma Clinic of Maryland located?
The office is located at 8630 Fenton Street, Suite 522, Silver Spring, MD 20910. It is open Monday through Friday from 8:30 am to 5:00 pm.
Who will I see at my appointment?
The practice is led by Vasif Kalfa, MD, a board-certified allergist and immunologist who completed his fellowship training in allergy and immunology at UCLA and has more than 20 years of experience. The care team also includes physician assistant Kimberly Joy McArthur, PA-C.
How do I schedule an appointment?
You can book an appointment online through the practice website or call the Silver Spring office at (240) 531-2902.
Does the practice accept my insurance?
Coverage depends on your specific plan. Please call the office or visit the Insurance & Fees page on the practice website to confirm your coverage before your appointment.
Is Allergy & Asthma Clinic of Maryland part of a larger network?
Yes. The practice is a member of Privia Medical Group, a multi-specialty medical group focused on coordinated, patient-centered care.
Medical Disclaimer: The information in this blog post is for general educational purposes only and is not intended as medical advice. It does not replace the advice, diagnosis, or treatment of a licensed medical professional. Every patient's situation is different. If you have concerns about your health or a related condition, please speak with a qualified physician or healthcare provider.
Disclaimer: The information provided on this blog is for general informational purposes only and is not intended as, and should not be considered, medical advice. All information, content, and material available on this blog are for general informational purposes only. Readers are advised to consult with a qualified healthcare professional for medical advice, diagnosis, or treatment. The author and the blog disclaim any liability for the decisions you make based on the information provided. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
