Food allergy

What is food allergy?

Food allergy is an allergic reaction, that is a hypersensitivity reaction to something in the food, which we can not tolerate.
Food allergy should not be confused with food intolerance, which is something quite different. In both cases you get symptoms when you eat a certain food in a normal or small quantity, so it can be easily confused.

Food allergy is very rare. Many refrain from eating things that they mistakenly believe they are hypersensitive to without being properly examined.
If you believe that you or your children suffer from food allergy, it is therefore very important to have the right diagnosis made, including a systematic review of diet and the symptoms. This is done best at one’s own doctor or a specialist in allergic diseases.

Why do you get food allergies?

In order to develop food allergies your immune systems must overreact to foreign proteins in the surroundings. The response must be carried out with specific IgE antibody. It is called a Type 1 allergy. Antibodies are the body’s antidote to foreign substances.

When exposed to proteins in foods, your body may develop specific IgE in such large quantities that it triggers an allergic reaction the next time you eat that particular type of food.

As a general rule you can not have an allergic reaction the first time you eat a new type of food. But this is only a qualified truth. Sometimes an allergic reaction is not due to a genuine food allergy, but to the fact that you already are allergic, for example to birch pollen. This phenomenon is called cross allergy.

Examples of food allergens

In principle, you can react allergic to all foods, but the most common allergens are:

  • Seafood
  • Milk
  • Fish
  • Soybeans
  • Wheat
  • Egg
  • Nuts
  • Fresh fruit
  • Vegetables
  • Peanuts

Cross reaction allergens

  • Birch cross reacts with hazelnut and other nuts, apple, pear, cherry, walnut, almond, plum, kiwi, potato peel, tomato and carrot.
  • Grass cross reacts with beans, lentils and green peas and peanuts.

How does food allergy feel?

The allergic reactions are very diverse and can start immediately after eating the food or may start several hours later. Typical symptoms are:

  • Swollen lips, face and / or throat
  • Tingling in the oral cavity and on the lips
  • Vomiting, stomach cramps, diarrhea
  • Headache
  • Fatigue, irritability
  • Hay fever
  • Asthma
  • Skin eruption, deterioration of child eczema, (atopic dermatitis), or hives
  • Very rarely anaphylactic shock, which is a circulatory collapse that requires emergency treatment with epinephrine.

The symptoms may one time be mild, the next time be life-threatening because of Asphyxia or anaphylactic shock.
It is therefore important not to expose yourself for provocations, only because you “will not be a burden”.
If you feel starting shortness of breath, you must immediately under medical treatment. Call 911 if necessary.

What you can do to prevent food allergies?

  • Pay attention to the things you are allergic to, and on whether any cross-reactions arise.
  • Get advice of a specialist in allergic diseases (an allergist).
  • Please note the symptoms and contact your doctor at the slightest doubt.

How does the doctor diagnosed food allergies?

The examination largely depends on how annoying the symptoms are.
Often it is possible to find another causes of the symptoms, such as the inability to digest certain foods (among other coeliac disease and laktose intolerans), non-immunological reactions (eg. histamine in shellfish) and minor food-poisoning. This is seen in about two percent of the population. It may also be a irritated colon or a chronic inflammation of the intestinal tract (ulcerosa colitis and Crohn’s disease) which can give similar symptoms.

If the symptoms are pronounced, and the suspected food allergy is justified, a proper clarification of what caused the disease will usually take place in a specialist in allergic diseases.

Allergy tests with, for example skin prick test or RAST (blood test) can be good to rule out allergies, but unfortunately, they often show reactions, which has no practical significance.

It is important that the allergy tests are made and examined by experts.

The allergist will often take you through the following program:

  • Two weeks on a normal balanced diet, with a carefully diary on the diet and the possible reactions.
  • If you during those two weeks observe relevant reactions, you should probably go ahead with a two-week period without the suspected food, where you keep a diary as before.
  • If the symptoms improve significantly, is the next step a food provocation. To begin with an “open” provocation in which both you and the examiner knows what you are eating. If symptoms appear, you will then be exposed to a number of double-blind placebo-controlled food provocation (DBPCFC), where neither the examiner or you knows what kind of food you are eating

In order to be diagnosed with food allergies, you should in most cases, go through the program outlined above.

Possible deterioration

  • Mucous membranes in the mouth and throat may swell so that breathing is troubled.
  • Asthma attacks and / or anaphylactic shock may be triggered.
  • It is getting increasingly difficult to get a proper nutritionally balanced diet.

Prospects for the future

Food allergy is a rare disease that primarily affects young children. Around three percent of young children are affected. Most grow from their allergy before the age of three years. Only about one percent of the adult population suffer from food allergies. Most of these can live a normal life with some limitations in their diet.

How are food allergies treated?

If, after a thorough investigation a food allergy diagnosis has been made, the main treatment is of course to stop eating the foods in question. The desease can not be cured medically, but it may possible to alleviate the symptoms by different measures. Typically antihistamines are used to alleviate the itching. But it is doubtful whether the anti-histaminerne have a preventive effect.