Common Food Allergies in Children and Adults – Causes, Symptoms, Test

What Is and What Is Not a Food Allergy?

A food allergy (Gk. allon = different, strange; ergon= activity) is an exaggerated reaction of the immune system to certain food substances otherwise not harmful for the man. These substances, when triggering an allergy, are called allergens. Practically any food may contain substances that can act as allergens; most of people with a food allergy are allergic to fewer than four foods at a certain time, though (5). Allergic reaction involves production of IgE antibodies and releasing of histamine into affected tissues. It is histamine that causes most symptoms like itchy skin or diarrhea.

Food intolerances, like lactose intolerance or fructose malabsorption, are NOT allergies because the immune system (antibodies) is not involved. Gluten intolerance and celiac disease are considered as autoimmune disease, but IgE antibodies and histamine are not released, so they are not food allergies. Various food intolerances determined by finding IgA antibodies in saliva or stool are also not food allergies. Beside obvious symptoms, only the presence of IgE antibodies in the blood confirms an allergy. Typical food allergy symptoms include tingling lips or itchy hives and diarrhea appearing within minutes (or, in delayed reaction, within several hours) after ingesting even a tinny amount of food. In food intolerances, symptoms are mostly confined to gastrointestinal tract.

Disorders, resembling food allergy:

Food Allergies in BABIES and CHILDREN

The following six foods commonly cause allergies in children (1):

  • Cow’s milk
  • Soy
  • Eggs
  • Wheat
  • Peanuts
  • Tree nuts (walnuts, cashews, etc.)

In infants, food allergies, especially to soy and cow’s milk, usually appear as diarrhea in their first days or months. It was found out that exclusive breast feeding may reduce the possibility of developing an allergy in high risk infants (2). Mothers should avoid foods that commonly cause allergies in infants since the allergens may pass into their milk. Children should not be offered cow’s milk until age 1, eggs until age 2, and peanuts, tree nuts, and fish until age 3 (3). Children usually outgrow allergies to soy, wheat, and eggs by the age of six; an allergy to cow’s milk often extends toward school years or far beyond (4). Allergies to peanuts and tree nuts are often life-long.

Children often react to fruit acids with a rash around the mouth – this is NOT an allergy.

Food Allergies in ADULTS

The following four foods commonly cause allergies in adults:

  • Peanuts
  • Tree nuts
  • Fish
  • Shellfish, especially shrimps, lobster, crabs, clams, mussels and oysters. Cross reactivity among shellfish is possible, so a person allergic to one shellfish should avoid all shellfish.

Allergies starting in adulthood are often life-long. Food additives (sulfites, monosodium glutamate) rarely cause an allergy (5). Sometimes, food allergies are triggered by exercise. Histamine from some cheeses, wines or spoiled fish may trigger symptoms that mimic food allergy.

Origin of Food Allergies

Food (and other) allergies commonly run in families. It is a predisposition (susceptibility) to develop an allergy, and not an allergy itself that is inherited. If one parent has an allergy, any child has a 50% chance to have it, and 75% chance, if both parents have it. (5).

Food allergens trigger production of specific IgE (immunoglobulin E) antibodies in the blood of a sensitive person (every different allergen triggers slightly different IgE antibody). Antibodies cause release of histamine in the gut, nose, throat, bronchi or skin what results in allergic symptoms.

Symptoms of Food Allergies

Histamine, released in the tissues may result in one or more of the following symptoms appearing within minutes or, in delayed response, several hours after food ingesting (1,5):

  • Tingling around the mouth or in the throat
  • Swelling of the lips or face
  • Runny nose
  • Coughing
  • Nausea or vomiting
  • Dizziness
  • Diarrhea
  • Feeling of “impending doom” (fear that something bad will happen)
  • Itchy skin; bumpy or patchy hives (urticaria) may appear anywhere on the skin
  • Chronic symptoms of food allergies are eczema and asthma
  • Difficulty breathing, wheezing, blood pressure drop, rapid heartbeat and fainting are symptoms of severe allergic reaction.
  • Death rarely occurs in food allergies.

Allergies are common in children, but may appear at any age.

Two Types of Food Allergy

In food allergy with an early response, symptoms appear within minutes to several hours after the meal. In delayed response, symptoms appear 12 to 72 hours after the meal (6). Any food may cause early or delayed response; symptoms may be of the same intensity in both types.

Pollen-Food Allergy Syndrome

Some people with allergy to pollens may get an allergic reaction after eating fresh fruits or vegetables. This is due to cross reactivity of immune system to resembling substances appearing both in pollens and fruits/vegetables. Cooking of fruits/vegetables typically prevents this type of allergic reaction. Foods that may cause pollen-food allergy.

Food Allergy Tests

Different tests to determine food allergy exist:

  1. In food challenge test, increasing amounts of samples of suspicious foods are given to the patient in certain intervals, and symptoms, which usually develop within 15 minutes, are monitored. Positive response (allergic symptoms) speak for allergy to a tested food. If a strong reaction is expected, a piece of food is put on the lip and a patient is observed for symptoms.
  2. In elimination diet test, one food a day is eliminated from the diet until symptoms disappear. Then, a suspicious food is introduced again; symptoms reappearance speaks for a food allergy.
  3. With a skin prick test, an early allergic response is tested. A drop of solution with a sample of suspicious foods is put on the skin of the upper arm and pushed into the skin by prickling the skin with a needle. Red inflammatory rash appearing within 20 minutes around the prick speaks for allergy to tested food.
  4. With a skin patch test, a delayed allergic response is tested. Several patches with samples of suspicious foods are glued to the back for 72 hours; skin reaction exceeding certain size speaks for food allergy.
  5. In RAST (RadioAllergoSorbent Test), some blood is drawn and then a sample of food is added to it. If a tested person is allergic to that food his/her blood contains specific IgE antibodies that react with the food sample; this reaction can be detected and speaks for food allergy. This test has many false positive results, so it is done only in individuals with expected dangerous reaction to skin tests, and in babies, in whom skin tests are not reliable. The test is expensive; results can be expected within a week.
  6. Blood eosinophils (a type of white blood cells) are usually (but not always) elevated in allergies so, together with IgE antibodies, they speak for an allergy but do not confirm it. Blood eosinophils may be also elevated in some parasites, like giardia or intestinal worms, certain blood diseases and in some other disorders.

Prevention and Treatment of Allergies

To date, there is no known cure for food allergies. An allergic person should avoid even small amounts of allergy-triggering foods. Cooking, in general, does not make foods non-allergenic, but it can make a certain food less or sometimes more allergenic. Symptoms of a mild allergy can be eased by over the counter (OTC) antihistamine pills but in severe allergic reaction an intramuscular injection of adrenalin is needed. Persons with severe food allergies should carry a warning bracelet and an anti-allergy kit with adrenalin (epinephrine) injector (“epi-pen”). Drugs should be always taken after an allergic reaction and not before eating since they have no protection value.

Related Articles:


  1. Food allergies in children (
  2. Breastfeeding may prevent food allergies in children (
  3. Infants – foods to avoid to prevent allergies (
  4. Milk and egg allergy (
  5. Food allergies in adults (
  6. Early and late allergic reaction (
About Jan Modric (249 Articles)
Health writer

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page

  • de quan

    When the body of the food intake of the antibody response produced, there will be an allergic reaction. The beginning of chewing some food, it would stimulate the allergic reactions, and some symptoms after a period of time will be and therefore are more difficult to find. Typical symptoms of food allergy stomach cramps, diarrhea, nausea, throat itching, rash, such as the beginning of serious vomiting, swelling of the face and tongue, and may congestive respiratory syncope.

    70% of food allergy in patients over 30 years of age, most children under the age of 6. More than 90% of allergens from milk, egg white, peanuts, wheat or soybean caused by allergens, and berries, shellfish, cereals, also played a role in pigment.

    Family control measures

    ????? identify food allergies

    To ensure that food is the root of the problem, and then only from time to rule out the possibility of diet food. Ruled out food allergy if the situation does not improve, and then try to rule out the possibility of food, first of all to restore the food intake. Unless you have a good discussion and a doctor, or do not rule out the diet. Because only a complete nutritional intake of the health and normal growth.

    If you are a true food allergy, it needs to be ruled out entirely. This is very difficult to achieve, because the packaging of food, convenience foods, fast foods sometimes contain unexpected materials, therefore, must be carefully read all the food ingredients label. Sometimes the food will be a different name. In addition, food manufacturers change the formula below is not particularly significant, it is recommended to buy pre-packaged foods, regardless of previous purchase, or carefully read the label better.

    The following are the three restaurants are often excluded from the adoption of models:

    ?????lling food allergy

    If you have allergy or food allergy symptoms, allergy should be tested first to determine the impact of your food allergy. There are two tests to detect food allergy: skin test and blood test needle stamps or adsorption (radioallergosorbent test) testing. Room stamps needle skin clinics, drop in a reduction of material to test your arm or back, and then sealed, the skin needle. If you are allergic to this material, this website will be swelling within 15 minutes.

    Certain foods need to assay blood samples for testing to see if you have their immunoglobulin E antibody. Test more than about a week. These two tests can only identify about 10% -15% of the type of food allergy, so, even if the result is negative, not be of much help. In recognition of the two tests found, doctors usually recommend that you do not rule out the diet, or eating. Not be ruled out because of eating suspect food allergies, and then re-started under the control of eating these foods, eat first, to determine which will cause allergic reactions. This process may take several months to complete, but test results can greatly enhance your immune system so that you do not have to suffer life-long. This is the best way of eating under the supervision of a doctor.

    ?????n-milk diet

    Can not drink milk (whether whole, low fat or skim), and even the food does not contain milk ingredients work; that is to say, contains the following components will not work for all foods: milk, dairy products, pulp , casein protein, lactose, Zhang dry milk, milk powder. The production of milk or milk containing foods, including the creamer, butter, cheese, yogurt, cheese, condensed milk, most ice cream, butter, most of the factory, coating low-fat butter, milk chocolate, pudding dessert category.

    Most of bread, cakes, cookies in milk, canned soup, as well as Western-style package. Breakfast cereals often contain milk powder. As for drinks, you should avoid the increase in coffee creamer, and milk drinks, such as the Iowa area, hot cocoa.

    ?????n-egg diet

    You have not only enough to avoid cooking the eggs in a different way, in any form to avoid food that contains eggs, including eggs, protein, dry egg. The following foods often contain eggs: pudding, ice cream, chocolate, wheat, eggs, fried rice, cakes, cookies, muffins, sauces, salad dressings and the United States now. Do not forget, eggs are often used as a bakery, and to increase the color of the material.

    ?????n-wheat diet

    Exclude such a possibility: namely, the need to avoid wheat on wheat, flour, starch, bran, malt, wheat meal. The following foods often contain wheat: bread, most crackers, most of porridge, most types of noodles and pasta, bread flour, bread flour things, such as sausages, hot dogs, all kinds of thick sauces, soup, or soy flour starch. Do not forget that the use of other grains, like rye, corn bread and other pastries are usually add some wheat production.

    ?????od Allergy gradually try to

    In accordance with the procedures for the elimination diet or fasting, you can try to add a small amount of diet food should be avoided, for example, once a teaspoon. And record the response after eating. 4-day cycle units, and different groups, daily food to eat, eat to repeat after four days. As far as possible every day to eat the food, but it is important that food should be more than four days each food. If the weekly intake of certain foods 4 or more times, these foods should be fasting for 30 days.

    After eating, if you think there was a slight swelling or headache, head discomfort, discharge, diarrhea, rapid pulse or heart palpitations, should immediately stop using these foods for 60 days, and then returned to the small number of restaurants.

  • punzelle

    My sister and I (both ‘mature’) get the same reaction to eating clams: we become extremely sleepy within a few hours after ingesting anything with clams in it, and must sleep — heavily, for at least a “long nap” if daytime, and then awaken very groggy. Neither of us have any known food allergies, and I can’t find this particular reaction mentioned anywhere else; has any reader also experienced something like this when eating clams? We both love seafood, too.

  • Jan Modric

    To punzelle.

    Paralytic shellfish poisoning, ciguatera fish poisoning, or other poisoning may occur when you eat fish/shellfish contaminated with saxitoxin, ciguatoxin.. that come from algae that fish/shellfish ingest and accumulate, especially during “red tide” in summer, or (in Caribbean area) at any time of the year.

    Can you say where are you from, and where are fish/shellfish you eat comming from?

    Furtther reading:

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  • DaveF

    Vehicle Head Trauma causing food allergies?
    My twin daughters have had very minor pet allergies all their lives. But that has been it. Never has Katie had any food or any other allergies. Last summer we were involved in a pile up on the highway. My daughter Katie took a hit on the centre of the forehead from her cell phone being in her hand. It swelled up and turned purple and you could see the impressions of the cell phone keypads. The very next day she had her first reaction ever to nuts. We did not know what was going on with her and her forehead where the cell phone made contact turned white. We took her to the hospital and she then had to have IV and we found she is now highly reactive to nuts and is getting worse with every reaction. The doctors that have looked at her say this is a very rare case and they suspect the trauma from the accident caused it but have no info. She has had three reactions in the past year all getting worse. And the one was from touching a doorknob that someone had touched after eating a peanut butter sandwich. She now has a double epée pen and 20 mins to get to hospital. She is now suffering depression, as she is always worried and suspect of everything she comes in contact with. Has anyone heard of these causes? There are costs associated with the life long commitment to her allergies now and no substantial evidence of cause. Is there research anywhere I can find documenting head trauma can cause life-threatening allergies?
    Thanks Dave

  • Jan Modric


    besides physical trauma, you should consider certain substances in the cell phone or its battery (nickel??) that your daughter has possibly inhaled or ingested during the accident. This could maybe cause a cross reactivity with nuts.

    It’s also possible, she has eaten some new food in days before the accident that caused cross reactivity with nuts, and the car accident was only a coincidence.

    So, the question for an allergologist would be: Which exact foods or substances can trigger allergy to nuts? She should maybe have additional tests then.

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