Signs you may have a food allergy

Chances are you or someone you know may be affected by a food allergy. The American College of Allergy, Asthma and Immunology states, “A food allergy reaction occurs when your immune system overreacts to a food or a substance in a food, identifying it as a danger and triggering a protective response.” While we may think of them as something you’re born with, food allergies can develop at any age. 

Dr. Gina Coscia, an allergy and immunology attending physician with Northwell Health in Long Island explains, “People react to foods in different ways. Some people can have a true allergy, and develop symptoms 30 minutes to a few hours after eating a food, or patients can also experience intolerances where it’s not a true allergy, but a particular food doesn’t make them feel good.” 

Reactions can be mild to severe (even life-threatening), and because your body may not react that same every time, most healthcare providers counsel patients to avoid those triggering foods in case they have a much worse reaction to something they’d previously had a milder response to. Allergy symptoms can impact the skin, GI tract, or even the cardiovascular and respiratory systems, so take them seriously and call your doctor if you suspect you have an allergy. These are some signs you should pay attention to. 

Tingling or itching

If you start experiencing tingling or itching in the mouth or throat after eating a certain food, Dr. Coscia said it could be a sign that you’ve got an allergy. Pay attention to whether it is a particular food or whether there is any difference in your reaction to cooked and raw versions of a food. “Tingling or itching of your lips and tongues are more subtle and should be watched for progression, but if you experience tingling or itching of your throat, that’s a sign that a more serious reaction may be developing. Any symptoms of your throat are things you should take seriously.” 

To give you a personal example, I grew up eating everything, but I didn’t realize until age 24 that my aversion to cherries (I didn’t like the way they made my throat itch) was related to an allergy. Most nuts had started to bother me too. At first I thought I was imagining it, but a trip to an allergist confirmed it wasn’t all in my head. “This probably won’t kill you,” he said, “but here — take this epi pen.” Because it turned out my issue was related to a birch pollen allergy (called cross-reactivity or oral allergy syndrome), I also had to cross a bunch of other fruits off the list. Then when I turned 30, shrimp made my throat itch so badly I had to give that up too. 

Trouble breathing, wheezing

Whether it sets in immediately or within a few minutes or hours, breathing difficulty is a serious sign of an allergic reaction. Feeling like your throat is tight and like it’s hard to draw a deep breath are also key indicators. Some people may notice they develop a cough or wheeze. Dr. Coscia told me, “Any difficulty breathing should be taken seriously. With wheezing, you might hear a high-pitched sound when you breathe or feel tightness in your chest.” Seek help ASAP. 

The thing that finally convinced me to make an appointment with an allergist was a trip to a raw vegan restaurant where pretty much every dish contained nuts. I struggled to draw a deep breath all night long afterward. In retrospect, I got super-lucky my reaction wasn’t worse.  

You may have heard of anaphylaxis — Dr. Vincent Pedre, a board certified internist and author of HAPPY GUT®: The Cleansing Program To Help You Lose Weight, Gain Energy, and Eliminate Pain, explained, “A true food allergy is characterized by anaphylaxis, which can involve the swelling [and] closing of the wind pipe (trachea) and bronchospasm (spasm of the small airways in the lungs, like in asthma), leading to breathing difficulties and possibly death.” 

If you start turning pale or blue, that means your oxygen may be cut off. Translation: call 911 right away.   


Swelling of the windpipe, Dr. Pedre explained, is one sign of an allergy, but swelling of the face, lips, tongue, throat, or other part of your body can also be a sign that you’re allergic to something. While you’re most likely to notice it within two hours of eating (and often within minutes), symptoms can sometimes take several hours to develop. When to freak out: if your tongue starts swelling, making it difficult to talk or breathe. Seek medical attention right away. 

Dr. Coscia also cautions to take note if that swelling comes with any other symptoms such as “itching, shortness of breath, chest tightness, vomiting, [or] feeling weak or faint.”

Hives, rash, or eczema

Breaking out in hives? Itchy all over? It’s not random! Even an eczema outbreak could be the result of a food allergy. Note if there is a particular area of the body where you get itchy or break out in hives or eczema. Not totally sure what you’re looking for? 

Hives, as Dr. Pedre told me, involves “a very uncomfortable rash that appears as raised red patches on the skin.” Eczema is similar, but a little different. It will appear as “a sometimes itchy rash that looks like areas of red, dry skin, which occasionally flake. It tends to occur along the inner folds of joints like the elbows, knees, fingers, [and] wrist but can happen anywhere on the body.”  

Dr. Coscia explained, “Itching may show up on the chest the arms, the arms, the abdomen — anywhere. If it’s just minor itching in one part of the body that usually indicates a mild reaction, but if it’s anything on your entire body or anything that involves difficulty breathing or vomiting or any sign of a systemic reaction, you should seek medical attention immediately.”


While it may be written off or attributed to something else, dizziness can actually be related to an allergy. Dr. Coscia told me that if after eating something “you feel very weak or faint as if you’re going pass out, you should call 911 immediately.”  

If you notice you always seem to feel dizzy, weak, or light-headed after eating a particular food (you may or may not know you’re allergic — sometimes this happens with accidental exposure to an allergen), it could mean you’re allergic. Fainting can even be a sign of a food allergy. Mild or intense, this is definitely a serious one, as sometimes that dizzy feeling can be an early sign of an anaphylactic reaction, she adds. Don’t brush this one off. Get help ASAP. 

Gastrointestinal discomfort

Sometimes allergic reactions show up as gastrointestinal distress. We tend to write off bathroom stuff as a bug or food poisoning, but if you experience stomach cramps, nausea, diarrhea, or vomiting, it could indicate an allergy, said Dr. Pedre. However, in some cases, Dr. Cosia explained, these symptoms may actually be related to an intolerance. “Lactose intolerance is often confused with a true milk protein allergy” because of some overlap in symptoms. However, “a true allergy to milk protein would involve hives, itching, shortness of breath, vomiting, or weakness and feeling like they’re going to pass out.”

Dietitian Linzy Ziegelbaum of LNZ Nutrition, LLC in Long Island, New York added, “It’s important for people to realize food allergies and food intolerances are not the same thing. While food intolerances can be uncomfortable and can make you feel horrible, food allergies can be life threatening.”

Dr. Pedre notes that while foods you have a true allergy to and that cause anaphylaxis “need to be avoided completely,” when it comes to food sensitivities, he generally recommends a functional medicine approach that involves “rebalancing the gut microbiome” and resolving gastrointestinal health issues that are often associated with allergies. “Western medicine focuses on symptoms,” he said, “whereas functional medicine focuses on resolving the root causes of symptoms.” Once the gut is healed, many foods that were reactive may be reintroduced in limited quantities. To be on the safe side, it’s best to work with a doctor or certified specialist on this one.

Methods for identifying potential triggers

“When someone suspects they have an allergy,” Ziegelbaum said, “I always recommend that they first see an allergist to screen for potential allergens. If allergy testing does not confirm a food allergy, then I recommend keeping a food journal to identify the cause of their allergy symptoms. Food journals can be helpful because it is hard to remember everything that we eat each day.” But just writing down what you eat each day is only the beginning. 

“It is important to include in food journals what you ate, the time you ate it, and any symptoms experienced. By keeping food journals, it makes it easier to see patterns and repeat offenders of certain foods.” She recommends having a registered dietitian who’s knowledgeable in food allergies and elimination diets to review your food diary and guide you on next steps.

Sometimes elimination diets may be used to help you weed out what’s causing a problem. If you suspect you have a sensitivity to something, Dr. Pedre recommends a 28-day (minimum) elimination diet to avoid suspected foods to get to what he calls a “blank slate” from which you can test the food as you reintroduce it to see if you still have a reaction to it. “Foods that are highly reactive may cause even worse symptoms once your system has been cleaned out,” he said.

What to expect at the allergist appointment

Once you’ve realized your symptoms are related to what you’ve been eating, it’s time to schedule an appointment with an allergist. 

Dr. Coscia said to expect a full work-up on your first visit. After a conversation about your symptoms, “if your allergist is suspicious of an allergy they’ll do either skin testing or blood testing. Based on those results, your allergist will help you figure out whether you need to avoid or those foods or not. You don’t want to put yourself at risk because you need to balance the risk of a serious reaction with excessive, unnecessary elimination, risk of nutritional deficiency, and fear.” In some cases, your doctor may have you do a food challenge, where you eat the food you’re potentially allergic to in the doctor’s office so they can monitor your symptoms.  

“Allergy shots are used only for environmental allergies,” Dr. Coscia explained, and not to treat food allergies. In most cases, avoiding the food or foods you’re allergic to is the main line of defense.

Getting used to your new normal

Ziegelbaum acknowledged that it’s totally normal to feel overwhelmed when dealing with a new dietary restriction. What will you eat? Will you be able to meet your needs? 

“Meeting with a registered dietitian trained in food allergies can help make the changes easier,” said Ziegelbaum. “Dietitians can help with recipe substitutions and product substitutions that make it less scary to have to change your diet. These substitutions make you feel like you are still able to eat a variety of foods and enjoy recipes you did not think you would be able to enjoy again. Dietitians are also able to evaluate someone’s diet and make suggestions to help them meet their nutrition needs, which can ease some of their fears and anxieties about diet change.” When you feel yourself getting frustrated, she adds, “Be patient, and remember that the reason for the diet is because of an allergy, and the change is necessary to help someone feel better and keep them safe!”

Dr. Coscia added, “If you’ve had a reaction to a food that has scared you or a loved one, it’s worth investing, or if you yourself have questions or concerns about a serious reaction you’ve had to a food in the past, it’s important to discuss it with an allergist.” 

If you’re overwhelmed by adjusting to a new restriction, talk to someone who can help you navigate the change and help you find new things you’ll love.