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Doctors Blog: Types of Food Allergy

Types of Food Allergies by COEM in Charleston, South Carolina

We eat to survive, and most of us enjoy eating. However, recent studies have found that almost 1 in 20 children and almost 1 in 25 adults are allergic to at least one food. Food allergies can range from being merely irritating to life-threatening. As a result, it is a must for each and every person to become aware of food allergies. Visit The Center for Occupational and Environmental Medicine (COEM) to get specialized care for all types of food allergies. For more information, contact us today or schedule an appointment online. We are conveniently located at 7510 North Forest Drive North Charleston, SC 29420.

Types of Food Allergies by COEM in Charleston, South Carolina
Types of Food Allergies by COEM in Charleston, South Carolina

Table of Contents:

What is food allergy?
Types of food allergies
Food and its allergies
Alternative treatments

What is food allergy?

Food Allergy is an abnormal response to a particular food, triggered by the body’s immune system. The immune system is responsible for identifying and destroying the invaders like bacteria and viruses in our body that can make us sick. A food allergy results when the immune system mistakenly targets a harmless food protein i.e. allergen as a threat and attacks it. Food allergy involves two aspects of the human immune response. One is the production of immunoglobulin E (IgE) – a type of a protein called an antibody that circulates in the blood and the other is the mast cell – a type of cell that occurs in all body tissues but is specifically common in the areas of the body that are typical areas of allergic reactions like nose, lungs, throat, skin and gastrointestinal tract.

The binding of IgE to particular molecular present in food triggers the immune response. The response may be mild, but at times it can cause a severe life-threatening reaction called anaphylaxis (explained further).

An allergic reaction occurs when the person who is predisposed to form IgE to certain foods, is exposed to that food. It is a process that includes two steps:

Step 1– The first time an individual is exposed to a food allergen; the immune system considers the food to be harmful and reacts accordingly by producing particular IgE antibodies to that allergen. These antibodies are circulated through the bloodstream and get attached to mast cells and basophils (basophils are found in the blood and also in the tissues that have become inflamed due to allergens)

Step 2– The next time that individual is exposed to the same food allergen; it binds to the IgE antibodies that are attached to the mast cells and basophils. This signals the cells to release massive amounts of chemicals such as Histamine – an organic nitrogenous compound that plays a key role in many allergic reactions, dilating blood vessels and making the vessel walls abnormally permeable. Depending on the tissue in which they are released, histamine will cause you to have various symptoms of food allergy.

Sometimes, a reaction to food is not a food allergy at all but another type of reaction called food intolerance. It is important to know the difference between these two. Some of the symptoms of food allergy and food intolerance are similar, but the differences between the two are very important. Food allergy reactions can be life-threatening, so people with this type of allergy should be careful to avoid their food triggers.

Being allergic to food also results in being allergic to a similar protein found in something else. For instance, if an individual is allergic to birch tree pollen, a primary airborne allergen responsible for symptoms in the springtime, the reactions may get triggered by peach, apple, pear, kiwi, plum, coriander, fennel, parsley, celery, cherry, and carrot. This type of food allergy is known as cross-reactivity. Cross-reactivity occurs when the immune system thinks one protein is closely related to another.

Studies have suggested that eight kinds of food cause 90 percent of food allergies.

• Milk
• Eggs
• Peanuts
• Wheat
• Fish
• Soy
• Nuts


An allergic reaction to food affects the skin, the respiratory tract, and the gastrointestinal tract and in rare or severe cases, it may also affect the cardiovascular system. Its symptoms typically appear within minutes to several hours of eating the allergic food. It is very important to understand, that children may describe these symptoms in a different way.

Mild symptoms may include the following:

• Tingling or itching in the mouth
• Hives (reddish, swollen, itchy areas on the skin)
• Nausea or vomiting
• Eczema (a persistent dry, itchy rash)
• Diarrhea
• Nasal congestion or a runny nose
• Redness of the skin and around the eyes
• Slight dry cough
• Sneezing
• Stomach pain
• Uterine contraction
• Itchy ear

Severe symptoms may include the following:

• Trouble swallowing
• Turning blue
• Chest pain
• Drop in blood pressure
• Wheezing or shortness of breath
• Loss of consciousness
• Sense of ‘impending down’
• Obstructive swelling of lips, tongue and throat

Severe symptoms alone or in combination with milder symptoms may be signs of severe or serious allergic reactions.

• Anaphylaxis

Anaphylaxis is a medical emergency. It includes a wide range of symptoms that occurs in many combinations. These symptoms are not life-threatening, but the most severe restrict breathing and blood circulation. Many different body parts are affected like:

• Skin – Itching, redness, swelling
• Nose – sneezing, stuffy nose, runny nose
• Throat – Itching, tightness, difficulty in swallowing, hoarseness
• Mouth – Itching, swelling of lips or tongue
• Heart – Weak pulse, passing out, shock
• Nervous System – Dizziness or fainting
• Chest – Shortness of breath, cough, wheeze, chest pain, tightness

Symptoms may begin within several minutes to several hours after exposure to the food. Anaphylaxis caused by an allergic reaction to a certain food is highly unpredictable. The severity of a given attack does not predict the severity of subsequent attacks. The response will vary depending on several factors, such as:

• Sensitivity to the food
• How much of the food an individual is exposed to
• How the food is entered into the body

Any anaphylaxis reaction may result in becoming dangerous and should be evaluated as soon as possible. Food allergy is the leading cause of anaphylaxis. However, medications, insect stings, and latex can also cause an allergic reaction that leads to anaphylaxis.

Eosinophilic Esophagitis (EoE)

Eosinophilic esophagitis (EoE) is a recently recognized chronic disease that can be associated with food allergies. It is increasingly being diagnosed in children and adults. Symptoms of EoE include nausea, vomiting, and abdominal pain after eating. A person may also have symptoms that resemble acid reflux from the stomach. In older children and adults, it can cause more severe symptoms, such as difficulty swallowing solid food or solid food sticking in the esophagus for more than a few minutes. In infants, this disease may be associated with failure to thrive. If you are diagnosed with EoE, you will probably be tested for allergies. In some situations, avoiding certain food allergens will be an effective treatment for EoE.

Types of food allergies

There are two categories of food allergies namely:

Immunoglobulin E (IgE) mediated– Symptoms result from the body’s immune system making antibodies called Immunoglobulin E (IgE) antibodies. These IgE antibodies react with a certain food.

Non-IgE mediated– Other parts of the body’s immune system react to a certain food. This reaction causes symptoms, but does not involve an IgE antibody. Someone can have both IgE mediated and non-IgE mediated food allergies.

Cross Reactivity or Oral Allergy Syndrome

Some people who have allergies to pollens, such as ragweed and grasses, may also be allergic to some foods. Proteins in the pollens are like the proteins in some fruits and vegetables. So, if your child is allergic to ragweed, he or she may have an allergic reaction to melons and bananas. That’s because the protein in ragweed looks like the proteins in melons and bananas. This condition is oral allergy syndrome.

Symptoms of an oral allergy syndrome include an itchy mouth, throat or tongue. Symptoms can be more severe and may include hives, shortness of breath and vomiting. Reactions usually occur only when someone eats raw food. In rare cases, reactions can be life-threatening and need epinephrine.

Allergic Proctocolitis

Allergic proctocolitis is an allergy to formula or breast milk. This condition inflames the lower part of the intestine. It affects infants in their first year of life and usually ends by age 1 year.

The symptoms include blood-streaked, watery and mucus-filled stools. Infants may also develop green stools, diarrhea, vomiting, anemia (low blood count) and fussiness. When properly diagnosed, symptoms resolve once the offending food(s) are removed from the diet.

Mixed reaction

Some children may have a mixed reaction where they experience both “IgE” symptoms, such as swelling, and “non-IgE” symptoms, such as constipation.

This often happens to children who have a milk allergy.

Exercise-induced food allergy

Sometimes a food allergy can be triggered after eating a certain food and then exercising vigorously. This can lead to anaphylaxis in severe cases, at times known as food-dependent exercise-induced anaphylaxis.

Food and its allergies


If a glass of milk causes significant symptoms like swollen lips, hives etc, you may have an allergy to casein – a protein in milk. Most dairy products contain casein, but not all. Since casein is a protein, it is found in dairy products that have higher protein content, such as milk, yogurt, kefir, cheese and ice cream. Dairy products that contain barely any protein, such as butter and cream, only have traces of casein. Casein is in a family of phosphoproteins that make up 80% of the proteins in cow’s milk. In fact, casein is found in all mammalian milk in varying quantities, including human milk, where it constitutes 25-45% of proteins. It is a complete protein that supplies all the essential amino acids – those that can’t be synthesized naturally by the body. It is also associated to gluten.

Symptoms of Casein Allergy:

• Swelling of the lips, mouth, tongue, face, or throat
• Skin reactions such as hives, a rash, or red, itchy skin
• Nasal congestion, sneezing, runny nose, itchy eyes, coughing, or wheezing
• Anaphylaxis (in rare cases)
• Wheat Allergy

Wheat is the major component of our daily diet. It is more common amongst children and is usually outgrown before reaching adulthood. Symptoms of wheat allergy reaction can range from mild, such as hives, to severe, such as anaphylaxis.

An allergic reaction to wheat involves IgE (immunoglobulin) antibodies to at least one of the following proteins found in wheat:

• Albumin
• Globulin
• Gliadin
• Glutenin (gluten).

The most common allergic reactions involve albumin and globulin. Allergy to gliadin and gluten are less common. Gluten allergy is often confused with Celiac disease.

The most common symptoms of wheat allergy are:

• Mouth irritation and possible swelling
• Nausea
• Throat irritation and possible swelling
• Urticaria – hives, an itchy rash (possible swelling of the skin)
• Vomiting
• Watery and/or itchy eyes
• Bloated stomach
Allergic rhinitis– nasal congestion
• Anaphylaxis
• Atopic dermatitis (eczema)

Gluten Allergy

A gluten allergy – not to be confused with gluten sensitivity or celiac disuse, is caused by an allergic reaction to a gluten protein. It is caused by gliadin, a glycoprotein that along with glutenin – a wheat protein, forms gluten. It is found in wheat and other related grains such as barley, oats, and rye. Gliadin is also one of the major allergens associated with wheat allergies and a trigger for celiac disease, a serious autoimmune disorder of the small intestine.


• Troubled breathing
• Ulcers in the mouth
• Asthma
• Depression
• Weight Loss
• Rash
• Swollen lips
• Anaphylaxis (in rare cases)

Soy Allergy

Soy allergy is a common food allergy especially among children. Allergic reactions to soy are typically mild; however, although rare, severe reactions can occur. Soybeans are a member of the legume family, which include plant species that bear seed pods that split upon ripening. Some examples of other legumes include beans, peas, lentils and peanut. People with a soy allergy are not necessarily allergic to other legumes.

Fish Allergy

Salmon, tuna and halibut are the most common kinds of finned fish to which people are allergic. More than half of all people who are allergic to one type of fish also are allergic to other fish, so allergists often advise their fish-allergic patients to avoid all fish.

A fish allergy can cause a very serious reaction, even if a previous reaction was mild. A child who has a fish allergy must completely avoid eating fish. Sometimes an allergist can test for allergies to specific types of fish, but until the culprits are known, it’s best for someone with a fish allergy to avoid all fish.

The pattern of symptoms following ingestion of fish and seafood is similar to that reported for other foods, including, nausea, sickness, diarrhea, abdominal cramps, wheezing, rhinitis, flushing, urticarial rashes and dramatic swelling.

Finned fish and shellfish do not come from related families of foods, so being allergic to one does not necessarily mean that you must avoid both.

Egg Allergy

Eggs are everywhere, not only are they served for breakfast, but they’re also in all sorts of foods — from muffins to meatloaf. But the question is what if you were allergic to eggs?

Egg allergy develops when the body’s immune system becomes sensitized and overreacts to the proteins available in the egg white and yolks. It is estimated that about 2 percent of children are allergic to eggs, although about 70 percent of these children may outgrow the condition by age 16.

Children who are allergic to eggs can have reactions ranging from a mild rash to anaphylaxis, a life-threatening condition that impairs breathing and can send the body into shock.

Tree nuts Allergy

Tree nut allergy is the second most common allergy in infants and young children. Approximately 0.4- 0.5% of American children have a tree nut allergy. Tree nuts are a common allergen reported to cause fatal and near-fatal allergic reactions. Tree nuts can cause a severe, potentially fatal allergic reaction. Tree nuts include, but are not limited to, walnut, almond, hazelnut, cashew, pistachio, and Brazil nuts. These are not to be confused or grouped together with peanut, which is a legume, or seeds, such as sunflower or sesame.

Peanuts Allergy

Peanut allergy is one of the most common food allergies. Peanuts can cause a severe, potentially fatal, allergic reaction (anaphylaxis). Allergy to peanuts appears to be on the rise in children. According to a certain study, the number of children in the U.S. with peanut allergy more than tripled between 1997 and 2008.

Peanut allergies tend to be life long, although studies indicate that approximately 20 percent of children with peanut allergy do eventually outgrow their allergy. Younger siblings of children allergic to peanuts may be at increased risk for allergy to peanuts.

Other Allergies

While the above allergies account 90 percent of all food allergic reactions, a person can be allergic to any food.

The list below is of foods of which allergic reactions have been reported too:

• Corn
• Gelatin
• Meat (beef, chicken, mutton, and pork)
• Seeds (sesame, sunflower, and poppy being the most common)
• Spices (caraway, coriander, garlic, mustard, etc.)


The first step to diagnose a food allergy is by the study of a thorough medical history of the patient. Later, the allergist may conduct the following tests:

Skin Prick Test

Food allergy symptoms are caused by the interaction between a food allergen and IgE. The Skin Prick test is one of the tests to diagnose it.

During the test, a drop of solution containing the allergen is placed on the forearm. When the test is of fruits and vegetables, fresh food is used instead of the solution. A small plastic probe or needle is used to prick or scratch the skin and a tiny amount of solution is allowed to enter just below the surface. This type of test is not painful and there is no bleeding. The test results usually appear in 30 minutes.

Blood Test

Blood test is used to measure the presence of IgE antibodies to specific foods. With the skin test, the results are immediate, but with the blood tests, the results may take several days to arrive. Unlike the skin prick test, the blood test is not affected by antihistamines and can be performed for people with extensive rashes that prevent using skin tests.

Oral Food Challenge

At times, even after performing skin prick and blood tests, an allergist is unable to arrive at a definitive diagnosis. In this case, you may be asked to undergo an oral food challenge (OFC), a highly accurate diagnostic test for food allergy. OFC has the potential to cause serious reaction; hence, it is performed by experienced allergists.

During this test, the patients are given the suspect food in measured doses, starting with small amount that may not trigger any symptom. Following each dose, the patient is observed for any signs of a reaction. If there is no symptom, the patient will be given increasingly larger doses.

OFC includes the following:

• Double-Blind, Placebo-Controlled Food Challenge (DBPCFC) – For example, if a patient is being tested for milk allergy, he/she may eat a piece of hamburger that contains milk powder, or a look-alike that has no milk in it. This process ensures that the test results are objective. Neither the patient’s anxiety nor the allergist’s preconceptions can influence the outcome.

• Single-Blind Food Challenge – In this test, the allergist knows if the patient is receiving the allergen, but the patient don’t.

• Open Food Challenge – Both the doctor and the patient know whether and not the patient is receiving an allergen. This type of challenge is most often done when a patient’s nervousness is unlikely to affect the results.

Food Elimination Diet

The elimination diet generally lasts two to four weeks. During this period, the patient will avoid the suspect foods while the doctor monitors the symptoms. If one or more of these foods is causing an allergy, the symptoms should disappear by the end of this period. In some cases, the doctor may add another step, gradually reintroducing a problem food to the diet. If the symptoms return, it is likely that the patient is allergic to that food.


Food allergies are often treated from several directions at the same time, such as eliminating allergens, strengthening the patient nutritionally, and modifying the patient’s immune response. The most important part of your treatment YOU will do, not your doctor. Food allergy is a very individual problem, and you know your body better than anyone else does. It may be difficult to take action because of your health, but if you want to get well, YOU must take responsibility for yourself.

Medication – The choice of medication depends upon the severity of the reaction. These medications are for controlling the allergy and not for curing it.

Antihistamines – Antihistamines are one of the best known allergy medications, and most of them are easily available at a pharmacy without prescription. They work well to relieve symptoms of different types of allergies.

Antihistamines are of different types, including tablets, capsules, liquids, nasal sprays and eye drops. Below are some of the antihistamines available:

Astelin, Astepro (azelastine) nasal sprays
• Atarax, Vistaril (hydroxyzine)
• Clarinex (desloratadine)
• Cyproheptadine (generic only)
• Emadine (emadastine) eye drops
• Livostin (levocabastine) eye drops
• Optivar (azelastine) eye drops
• Palgic (carbinoxamine)
• Xyzal (levocetirizine)
• Mast Cell Stabilizers

Mast cell stabilizers are used to block the release of immune system chemicals that contribute to the allergic reactions. These drugs are safe, but usually need to be used for several days to reach full effect.

• Cromolyn (Nasal spray and eye drop)
• Lodoxamide
• Pemirolast
• Nedocromil
• Decongestants

Decongestants are used for quick, temporary relief of nasal and sinus congestion. They can cause insomnia, headache, increased blood pressure and irritability. They are not recommended for women who are pregnant or for people with high blood pressure, cardiovascular disease, glaucoma or hyperthyroidism.

For example: pseudoephedrine- Sudafed, Afrinol, others, Cetirizine (Zyrtec-D), Desloratadine (Clarinex-D), Fexofenadine (Allegra-D), Loratadine

The steroids used for the treatment of allergies are corticosteroids and are almost identical to the natural hormone, cortisol, which is produced by the body’s adrenal glands. But with any medication, it is important to follow the dosage, as prescribed by a health practitioner, as over-use of any medication can be harmful.

For example:

• Budesonide (Rhinocort Aqua)
• Fluticasone furoate (Veramyst)
• Fluticasone propionate (Flonase)
• Mometasone (Nasonex)
• Triamcinolone (Nasacort Allergy 24 Hour)


The use of adrenaline (epinephrine) as an emergency allergy treatment is well understood by doctors, and it has saved many lives. It is used to treat anaphylactic shock, where the sudden, high levels of histamine and other substances released during an allergic reaction cause the patient to have difficulty breathing, and can also cause loss of consciousness. Research has shown that the sooner adrenaline is given once an anaphylactic reaction has started, the better the health outcome for the patient. This makes rapid treatment of anaphylaxis possible, rather than having to wait for ambulances carrying the medication to arrive.

The symptoms of some allergic conditions can increase the likelihood of localized infections. In particular, irritated skin caused by eczema can be vulnerable to infection, as can the nasal sinuses of people who suffer from hay fever or perennial rhinitis. For this reason it is important that infections are diagnosed and treated as soon as possible.

Leukotrienes are chemicals released by the immune system that cause swelling and secretion, and can cause allergy symptoms to persist. Anti-leukotrienes reduce inflammation and mucus production and work in a similar way to steroids, but with fewer side effects.

Anti-IgE drugs

The IgE antibodies are the most common cause of the immune system reacting to an allergen and initiating an allergic response. New anti-IgE drugs are being developed, which aim to take the IgE antibodies out of circulation. A number of studies have been conducted using anti-IgE drugs as an add-on treatment for people with severe allergic asthma. They showed that the anti-IgE medication could allow some people to reduce, and even stop, their inhaled steroid treatments.
Calcineurin inhibitors

Calcineurin inhibitors are a new treatment, currently available as two creams – Tacrolimus and Pimecrolimus (also known as Protopic and Elidel) – for use on children over the age of two. They work by reducing the sensitivity of the immune system when the skin comes into contact with an allergen.

Alternative treatments

Allergens are often associated with weak adrenal, immune and digestive functions. Alternative treatments help to support and improve these functions and also help in alleviating the symptoms. The following are some:
• Nutritional Treatment
Alterations and changes in nutritional intake help in reducing allergic symptoms. The diet should contain, moderately low-fat, high-complex carbohydrates. Drinking ½ of body weight in ounces of water daily is a must.
The following should be included:

• Dark green leafy vegetables
• Nettles, bamboo shoots, cabbage, beet tops, beets, carrots, yams
• Onions, garlic, ginger, cayenne, horseradish
• Deep yellow and orange vegetables
The following should be eliminated:

• Foods causing allergies
• Citrus fruit
• Alcohol, caffeine, and dairy products
• Food coloring (tartrazine)
• Sugar
• Wheat
Supplements, Vitamins and Minerals
• Flaxseed oil
• Probiotics (e.g., lactobacillus acidophilus and Bifidus) -. Probiotics are bowel microflora organisms—microscopic bacteria that normally inhabit the intestines.
• Multivitamin
• Bioflavonoids (e.g., quercetin, catechin, hesperidin) – When symptoms are severe, take up to 6 grams. Bioflavonoids are natural antihistamines and strongly anti-allergenic. Bromelain and vitamin C can enhance the action of bioflavonoids.
• Vitamin A
• Vitamin C – Bioflavonoids are natural antihistamines and strongly anti-allergenic. Bromelain and vitamin C can enhance the action of bioflavonoids.
• Vitamin E
• Zinc
Herbal Medicine
Many plants have therapeutic properties and one only has to remember that digoxin comes from the Foxglove, salicin from the bark of the Willow tree and opiates from the glorious Poppy. Herbal remedies such as the Ma Huang plant (Ephedra sinica) which contains ephedrine has been used to treat asthma for 5000 years but there is very little evidence that herbal medicines in general confer any major benefit. In some cases they may even be hepatotoxic. One recently noted exception is the use of traditional Chinese herbal tea in the treatment of atopic eczema. Ling zhi (Reishi Mushroom) is another eastern herbal preparation with steroid like properties used to treat allergies. Butterbur has been advocated in hay fever.

• Allium cepa – for bland, non-irritating discharge from eyes; copious, watery, acrid discharge from nose; hoarseness; and feeling better in cool air and open room.

• Euphrasia – for symptoms such as copious, watery, acrid discharge from eyes; non-irritating discharge from nose; dry, hard cough; much sneezing; diarrhea; and feeling worse in open air.

• Natrum muriaticum – for watery or egg white-like discharges; cold sores; no sense of taste or smell; headaches; and feeling better outside.

• Nux vomica – for runny nose in daytime, then dry nose at night; violent sneezing; nose feels blocked but there is watery nasal discharge through one nostril; and feeling worse outside.

• Wyethia – for extreme itching in the nose and throat; throat feels swollen; back of throat is dry and burning; and sensation as if something were in nasal passages.

Acupuncture is an ancient Chinese form of treatment that involves inserting tiny needles into specific meridians or areas of the body. It has been found to be particularly useful for pain relief and the practice has grown remarkably in recent years. Claims that the use of acupuncture is useful in treating allergies, in general, are not based on well-performed clinical trials.
This article has successfully proved that ‘allergy’ is more than just a runny nose; it can be the reason for a lot of problems and symptoms. At The Center for Occupational and Environmental Medicine (COEM) we have successfully identified the cause of chronic disease and disorders through comprehensive diagnostic evaluation, utilizing allergy and sensitivity testing as needed. We believe in helping the patients return home in good health. We serve patients from Charleston, Mt. Pleasant, Summerville, North Charleston SC, Ladson SC, Hanahan SC, James Island SC, John’s Island SC, Daniel Island SC, all of South Carolina, Nationally, and Internationally. Patients routinely fly into Charleston to be evaluated by COEM and to enjoy this beautiful city which is a Condé Nast and Travel and Leisure Top Domestic and International Tourist Destination.

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