If bothersome mouth symptoms are not going away with the usual treatments, investigate food allergies, food sensitivities, and irritants. In people who are truly allergic, foods can cause swelling of the lips, mouth, tongue, and throat. In less serious situations, a person with pollen allergy may be reacting to raw fruits and vegetables (known as pollen food allergy syndrome). On the other hand, a delayed food sensitivity could contribute to mouth sores, burning mouth, bleeding gums, or a rash around the mouth. Food reactions could contribute to poorly-formed enamel and tooth decay. Not all food reactions involve an immune response, some are simply irritating or toxic to the oral tissues. Testing and treatments at the end of this blog help to identify the most common problem foods, eliminate them, and rebuild the mouth lining and the oral-immune system. With one in ten adults experiencing food allergies, we cannot afford to overlook the role of food reactions in difficult-to-solve oral diseases.


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Diagnostic Solutions Laboratory offers cutting-edge tests for the integrative and functional medicine industry. The IgG Food Explorer is a comprehensive, accurate, and affordable test. It can be combined with the IgE Explorer test.


Allergic Reactions Can Cause These Mouth Symptoms:1,2

  • Swollen lips, mouth, tongue, or throat
  • Inflamed, red, dry, scaly, itchy, burning lips (cheilitis)
  • Red, swollen, inflamed gums (gingivitis)
  • Canker sores or inflammation inside the mouth, cheeks, inside of the lips, or tongue (stomatitis)
  • Red rash around the mouth with bumpy, itchy, burning, flaky skin (perioral dermatitis)
  • Burning, scalding, tingling in the mouth with no known cause (burning mouth syndrome)
  • Inflamed mouth lining with white, lacy patches, red, swollen tissues, or open sores (oral lichen planus or lichenoid tissue reaction)
  • Weak or damaged tooth enamel
  • Mouth breathing due to nasal congestion


IgE Food Allergies Versus IgG Food Sensitivities and the Mouth

The mouth gets exposed to so many things every day. From foods to inhalant allergens like pet dander, from chemicals in toothpaste to medications, from food additives to preservatives, cosmetics, and dental materials. When problem foods or chemicals come into contact with the mouth, they can cause symptoms by directly damaging the tissue, or by triggering an allergic reaction.

Certain chemicals can irritate or damage your mouth on contact- when they touch your skin or your mouth lining. They do this without engaging the immune system.1 These are non-allergic reactions. For example, toothpaste ingredients, gum, lipstick, medications, and sometimes mercury can cause skin or mouth irritation (contact dermatitis). Food allergy and food sensitivity blood tests will not be able to reveal irritants or toxins, because the immune system is not involved.

On the other hand, when we have allergic immune reactions to foods, it means that the immune system is overreacting to a normally harmless food.3 Most of us know someone who has a bona fide food allergy. True food allergies can be to peanuts, strawberries, or milk, for example. This type of allergy involves immunoglobulin E (IgE) and usually starts right away after getting exposed to the allergen. When a person has an IgE antibody to milk, for example, IgE antibodies are carried around in the blood. When the person drinks milk, it binds to the IgE antibody for milk in their blood, releasing histamine and setting off an inflammatory domino effect. That’s why an IgE allergic response can set off a whole-body severe allergic reaction (anaphylaxis) and can be very dangerous: the digestive tract, heart, brain, lungs, nose, and eyes. IgE anaphylactic food allergies are well known to manifest in the mouth. Hives or red welts on the skin can be a signal of IgE allergies. Allergies can run in families, as well as the related allergic symptoms eczema and asthma.

You can also have food sensitivities, which involve IgG antibodies. These are not dangerous food reactions like IgE allergies. Unlike food allergies, IgG food sensitivities can cause symptoms long after getting exposed to a food allergen- one to three days later. IgG antibodies to foods have been documented in irritable bowel syndrome, eosinophilic esophagitis, and childhood obesity. There is debate about their usefulness in the world of mainstream allergists. In integrative and functional medicine however, these food sensitivities are considered a possible problem for the immune system and they can be key to resolving chronic illnesses.

As you might imagine, it’s easier to pin down what foods are to blame for immediate allergic reactions. They happen almost right after eating a problem food. Delayed food reactions can be more difficult to identify since so much time can pass before symptoms begin. I also have seen food allergy IgE antibodies in people who didn’t have the symptoms. For this reason, testing and elimination diets are important to help figure out which foods are the culprit. I always recommend testing both IgE and IgG food reactions in difficult-to-solve cases. The lab results may just surprise you.


Allergies Can Cause Swollen Lips, Mouth, Tongue, and Throat

Classic IgE food allergies can cause lip swelling and tongue swelling immediately (usually within a few minutes to hours of eating the food). They can also cause itching in the mouth and tightness in the throat. Food allergies are infamous for triggering shortness of breath, wheezing, and coughing.

Treatment for IgE allergies is 100% avoidance of the problem food. Treatments may be needed to stop the allergic reaction in the moment (epinephrine or an EpiPen). On the other hand, medications may be needed to manage symptoms of food allergies or other allergic symptoms, such as eczema or asthma. Some children will grow out of a food allergy, others won’t. IgE food allergies should not be confused with oral allergy syndrome, which we discuss next.

Common IgE Food Allergies That Can Cause Mouth Symptoms Are:

  • Egg
  • Fish
  • Milk
  • Peanut
  • Shellfish
  • Soy
  • Tree nuts
  • Wheat

The tongue may also be affected in people with celiac disease or gluten sensitivity. People with celiac disease have a characteristic swollen, red, smooth tongue. The tongue may be missing the little bumps or the crease that goes down the middle of the tongue. Celiac disease may also present with a geographic tongue, which earns its name because the tongue has shapes on it like a world map. Geographic tongue is caused by inflammation, but is considered harmless.

Allergens Can Cause Itchy Mouth or Scratchy Throat

Certain foods can make your mouth itchy, especially if you already have pollen allergies. Known as oral allergy syndrome (or pollen food allergy syndrome), this happens when people with seasonal allergies develop food reactions, especially when they eat fresh fruits and vegetables. The reason for the confusion is that the immune system sees the pollen and the foods as similar.

For example, a person may have bad hay fever symptoms during allergy season (sneezing, coughing, watering eyes) when they inhale ragweed pollen. At another time, when they eat watermelon, it triggers an itchy and uncomfortable mouth. The immune system misdirects its attack not just to ragweed, but also to watermelon. That’s because the ragweed pollen and watermelon share a similar protein. This allergic reaction may include lip and facial swelling, tingling of the mouth, uncomfortable throat, and itchy ears and nose.


Pollen Food Allergy Syndrome Can be Triggered by These Food Reactions:

  • Birch pollen: apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear, plum
  • Grass pollen: celery, melons, oranges, peaches, tomato
  • Ragweed pollen: banana, cucumber, melons, sunflower seeds, zucchini


Similar to IgE food allergies, pollen food allergy syndrome can cause swelling of the lips, mouth, tongue, and throat. However, it rarely causes an anaphylactic reaction. It doesn’t usually cause symptoms all over the body. Symptoms of pollen food allergy usually go away once the person swallows the food. The treatment for pollen food allergy syndrome is to avoid raw fruits and vegetables and eat cooked versions instead. Allergists believe that patients suffering from this can continue eating the problem foods because they don’t seem to lead to more allergies or symptoms downstream. However, I would advise someone in this situation to do further work with an integrative and functional medicine provider to tune up their immune system, reduce their pollen and food allergies, and strengthen their barriers. Ignoring the symptoms of immune system dysfunction is not usually a wise strategy.

Gluten and Food Allergies Can Lead to White Spots on Teeth

Certain foods can spell trouble for teeth. Teeth are the hardest mineral structure in the body. When they don’t have enough minerals in their structure, they are weak or hypomineralized. Dentists call these “enamel defects” or “hypoplasia.” Teeth can be discolored. They may look yellow or brown. Teeth may have white, yellow, or brown spots on them.

Eighty-five percent of people with celiac disease have problems with their tooth enamel. For adults, this could mean “bad teeth,” extractions, cavities, and tooth loss. Celiac disease teeth may show little pits on them or bands across them. Teeth enamel may be mottled or translucent-looking. In celiac disease, a person has an autoimmune reaction to gluten, a protein found in wheat. It can damage teeth and cause nutritional deficiencies until the person goes on a gluten-free diet.

Poor tooth enamel 4,5 is believed to affect 13-14% of the world’s children.6 MIH (or molar-incisor hypomineralization) is when permanent teeth have defects in their enamel. These teeth can be sensitive, break down more easily after emerging through the gums, and are more susceptible to cavities (tooth decay).6 MIH is usually diagnosed in children before age 10. You may recognize the look of hypomineralized teeth: teeth with large white splotches on them or patches of discoloration.

MIH is significantly associated with atopic dermatitis and food allergies as well as allergic rhinitis and asthma.4,5 Children with these allergic conditions are more likely to have enamel defects, suggesting that food reactions could be harming their teeth at a critical time in development.


Foods Can Trigger Mouth Sores

Food reactions can cause canker sores or aphthous ulcers. In one study, patients with canker sores were more likely to have allergic reactions to fruits and vegetables.2 Another study showed people with canker sores were more likely to have allergic responses to animal fur and house dust. They were also more likely to have food intolerances.7 Cutting out problem foods from the diet (an elimination diet) helps doctors and patients identify what food allergens are contributing to chronic canker sores.8 Reactions to sodium lauryl sulfate in toothpaste can also cause canker sores, as well as reactions to food additives (e.g., benzoic acid) and/or flavors (e.g., cinnamaldehyde).1

Food Reactions Can Lead to Burning Mouth or Burning Tongue

The cause of burning mouth syndrome is still unknown. Whether burning mouth is an allergic reaction is debated. However, some foods, food additives, metals, and plastics have been implicated as potential causes of burning mouth syndrome. Instant coffee, peanuts, and chestnuts have been linked to burning mouth syndrome. In a study of people with various oral diseases, 40% with burning mouth syndrome had immediate allergic reactions to foods and additives. The worst culprits for burning mouth based on skin prick testing were: mushrooms, fruits, vegetables, and milk. Allergic reactions to certain food additives were also detected in patients with burning mouth.1 Children with celiac disease may experience burning tongue.

Food Allergies or Sensitivities Can Cause Mouth Breathing

Many people cannot breathe easily through their nose. Food allergies9 and sensitivities are notorious for causing nasal congestion.10 Food sensitivities, or delayed food reactions, can cause symptoms hours or days after consuming the problem food. The premier example is milk and dairy products. One way to remember that milk products may be making it hard for you to breathe is this pneumonic, “milk makes mucus.” Although this century-old saying has been rebuked, many allergists recommend avoiding it and people report less congestion and drainage when they remove dairy products. Gluten from wheat can trigger nasal congestion, making it hard to breathe. A person can have a wheat allergy, a gluten autoimmune response (celiac disease), or a gluten sensitivity. Food allergens are not the only problem. Inhalant allergens such as pollen, dust mites, or pet dander can also contribute to nasal congestion, mouth breathing, and the oral health problems that come along with it.


Food Allergies, Leaky Gums, and the Oral Microbiome

In a perfect world, the immune system tolerates all the foods and metals and chemicals that come into our mouths every day. If the mouth lining barrier is strong, the oral microbiome is built up, and the immune system is healthy, then everything should hum along happily. There are no food allergies. This state of perfect harmony along the entire gastrointestinal tract is called “oral tolerance.”

Unfortunately, when this happy balance gets disturbed, it can lead to problems. Leaky gums can occur when the oral mucosal barrier gets broken down and damaged. Much like leaky gut, when the mouth lining gets broken down, food proteins, bacteria, and chemicals can get into the bloodstream where they don’t belong, setting off inflammation and disease. I explained the concept of leaky gum syndrome in an earlier blog. If a person has inflammation in the mouth, or is getting continued exposure to problem foods, it could cause leaky gums.11,12 In a review paper on allergies and autoimmune diseases that affect the mouth, the authors propose that leaky gums could be a key player in developing a more severe allergic response to foods. In other words, a leaky mouth barrier could contribute to more food allergies.13

It is all the more important for clinicians and dentists to identify food allergies or food sensitivities as a way to turn off leaky gums and heal the mouth barrier. In turn, improving the integrity of the oral barrier may help prevent further allergic reactions and improve oral tolerance.

Last but not least, the oral microbiome promotes tolerance of food allergens. It encourages a healthy immune response to foreign foods, chemicals, and friendly bacteria. Build the oral microbiome to calm down inflammation in the mouth and improve immune function.


Metal Allergies, Food Additives, Fragrances, and Medications Can Harm the Mouth

Though not the focus of this blog, many dental products can cause allergic reactions in the oral cavity and around the lips. Examples are antiseptics, latex gloves, metals, mouth rinses, and more. Numerous studies show that people can have allergies to metals in dental or orthodontic materials such as mercury, cobalt, and nickel. Allergic reactions to medications can harm the mouth, contributing to oral lichen planus and mouth sores.10 Other chemicals such as “fragrance mix,” or food additives such as benzoate, can cause allergic reactions in the mouth.  If you have unexplained burning mouth syndrome, canker sores, swollen or itching lips, or other mouth symptoms that no one can figure out, you need to investigate these. Find a biological or holistic dentist to help evaluate the materials in your mouth and if they are contributing to your chronic symptoms.


Foods Could Be to Blame for Chronic Unexplained Mouth Problems

Symptoms in the mouth suggest that there is a problem that needs to be fixed. Food allergies or sensitivities can cause swollen lips, canker sores, burning mouth syndrome, oral allergy syndrome, and weakened tooth enamel with spots. Clinicians and dentists need to be thinking about food reactions when there are chronic oral symptoms that do not respond to the usual treatments. Consumers, you can turn your health around for the better when you and your healthcare team pinpoint what food or chemical is causing a problem in your mouth. For mouth sores that won’t go away, burning tongue, spots on teeth, and red, swollen lips or gums, clinicians and patients should work together to determine if food allergies, sensitivities, or irritants are the root cause. Testing and treatments will help to reduce inflammation, turn off the overactive immune response, and heal tissues.

Treatments for Food Allergies or Food Sensitivities

If you have mouth inflammation, irritation, burning or tingling sensations, mouth sores, or dry itchy lips that will not go away, you and your healthcare team should investigate food reactions. Work with a provider to order allergy testing. The test results can help pinpoint problem foods or food additives Eliminate foods for a few months that may be causing issues. Build up the oral microbiome, heal the tissue in the mouth, and supply the vital nutrients for the mouth to repair itself.

  • Test IgE food allergies and IgG food sensitivities, such as the IgE & IgG Food Explorer from Diagnostic Solutions Laboratory
  • Celiac disease blood test
  • Skin prick allergy testing may be used by allergists
  • Elimination diet, especially remove the most common allergens such as dairy, wheat, eggs, corn, and soy (with later reintroduction to watch for symptoms)
  • Keep a food diary and pay attention to when your symptoms appear in relation to food, dental hygiene products, or other exposures
  • Dentists should test for allergic reactions before placing permanent dental materials in the mouth
  • Remove food additives and preservatives
  • Avoid raw fruits and vegetables if you have oral allergy syndrome; eat cooked fruits and vegetables instead
  • Swap out your toxic toothpaste and floss for non-toxic options
  • Heal the mouth lining with L-glutamine, aloe vera juice, slippery elm, and zinc carnosine
  • Test the oral microbiome
  • Take probiotics
  • Eat a whole foods diet rich in prebiotics
  • Take the right vitamins for oral health to build healthy tissues and immune defenses

Photo by Eye for Ebony on Unsplash


Diagnostic Solutions Laboratory bridges the gap between healthcare providers and the clinical laboratory by offering cutting-edge laboratory tests such as GI-MAP, OMX (Organic Metabolomics), IgG Food Explorer, IgE Allergy Explorer, CytoDX, and GenomicInsight. Designed to identify underlying root causes of symptoms and disease, our test results give practitioners the tools needed to formulate personalized treatment protocols for optimized patient outcomes. Our commitment to education and service ensures both practitioners and their patients will benefit from the latest research.



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  2. Domic I, Budmir J, Novak I, Mravak-Stipetic M, Lugovic-Mihic L. Assessment of Allergies to Food and Additives in Patients with Angioedema, Burning Mouth Syndrome, Cheilitis, Gingivostomatitis, Oral Lichenoid Reactions, and Perioral Dermatitis. Acta clinica Croatica. Jun 2021;60(2):276-281. doi:10.20471/acc.2021.60.02.14
  3. Marwa K, Kondamudi NP. Type IV Hypersensitivity Reaction. StatPearls. StatPearls Publishing. Copyright © 2023, StatPearls Publishing LLC.; 2023.
  1. Hernandez M, Mendioroz J. Molar-Incisor Hypomineralisation and Allergic March. Acta Stomatol Croat. Jun 2020;54(2):130-135. doi:10.15644/asc54/2/2
  2. Hernandez M, Boj J, Espasa E, Planells P, Peretz B. Molar-Incisor Hypomineralization: Positive Correlation with Atopic Dermatitis and Food Allergies. The Journal of clinical pediatric dentistry. 2018;42(5):344-348. doi:10.17796/1053-4625-42.5.4
  3. Rodd HD, Graham A, Tajmehr N, Timms L, Hasmun N. Molar Incisor Hypomineralisation: Current Knowledge and Practice. International dental journal. Aug 2021;71(4):285-291. doi:10.1111/idj.12624
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  7. Khammissa RAG, Chandran R, Masilana A, Lemmer J, Feller L. Adverse Immunologically Mediated Oral Mucosal Reactions to Systemic Medication: Lichenoid Tissue Reaction/Interface Dermatitis-Stomatitis, Autoimmune Vesiculobullous Disease, and IgE-Dependent and Immune Complex Reactions. J Immunol Res. 2018;2018:7645465. doi:10.1155/2018/7645465
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  9. Rodríguez Del Río P, Díaz-Perales A, Sánchez-García S, et al. Profilin, a Change in the Paradigm. J Investig Allergol Clin Immunol. 2018;28(1):1-12. doi:10.18176/jiaci.0193
  10. Gomez-Casado C, Sanchez-Solares J, Izquierdo E, Diaz-Perales A, Barber D, Escribese MM. Oral Mucosa as a Potential Site for Diagnosis and Treatment of Allergic and Autoimmune Diseases. Foods. Apr 28 2021;10(5)doi:10.3390/foods10050970

Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, M.S.

Cass Nelson-Dooley, MS, is a researcher, author, educator, and laboratory consultant. She studied medicinal plants in the rain forests of Panama as a Fulbright Scholar and then launched a career in science and natural medicine. Early on, she studied ethnobotany, ethnopharmacology, and drug discovery at the University of Georgia and AptoTec, Inc. She joined innovators at Metametrix Clinical Laboratory as a medical education consultant helping clinicians use integrative and functional laboratory results in clinical practice. She owns Health First Consulting, LLC, a medical communications company with the mission to improve human health using the written word. Ms. Nelson-Dooley is an oral microbiome expert and author of Heal Your Oral Microbiome. She was a contributing author in Laboratory Evaluations for Integrative and Functional Medicine and Case Studies in Integrative and Functional Medicine. She has published case studies, book chapters, and journal articles about the oral microbiome, natural medicine, nutrition, laboratory testing, obesity, and osteoporosis.