What Is The Difference Between Intolerance And Allergy?

Food allergy though commonly confused with food intolerance, are different. Food allergy triggers an immune response to the body, while food intolerance involves the digestive system due to an enzyme deficiency.

Apart from that, they differ greatly in the causes, symptoms, and effects.

Observing symptoms and reading an article describing intolerance and an allergy is a sure easy way of identifying the reactions.

Food allergy

A food allergy occurs whereby the immune system is exaggerated by a food protein, triggering the body to respond to the protein incorrectly as if it’s infectious. The immune system releases chemical histamine.

An allergic reaction to the food activates antibodies to the specific food causing the body to react differently from mild to severe life-threatening reactions.


The onset of allergic reactions to food show soon after eating, usually within 2 hours or 4-6 hours

Symptoms of a food allergy include:

  • Difficulty in breathing
  • Throat tightening and coughing
  • Swollen tongue, the roof of the mouth, and general face swelling
  • Vomiting
  • Abdominal pains
  • Blood pressure fluctuates, drops.

Some symptoms are potentially life-threatening, leading to a condition called anaphylaxis


Food allergies originate from a weakened immune system where a food protein is mistaken for an infectious threat by the body.

Anyone is susceptible and can be affected by a food allergy. The allergy is not tied to a certain type of food and can occur to any foods you consume regularly.

Common food triggers include dairy (milk/eggs), nuts, fish, meat, certain fruits, and vegetables.

Types of food allergies

  1. Immunoglobulin E (IgE) mediated: The body’s immune system produces antibodies IgE. This type of allergy happens almost immediately after food consumption. It’s the most common and may lead to anaphylaxis.
  2. Non-IgE mediated: The symptoms of this allergic reaction take longer to develop, sometimes even several days. The reaction does not involve IgE antibodies.
  3. Mixed IgE and non-IgE-mediated: Both types of reactions can occur simultaneously after food consumption.

Allergic tests

One may attend an allergy clinic for testing. The tests, however, depend on the type of allergy:

Skin prick testing

Usually conducted for people with IgE mediated food allergy.

Drops of standardized extracts are placed on the arm and skin pierced with a small lancet, allowing the allergen to come into contact with your blood.

Itchiness or redness indicates a positive reaction.

Blood test

Blood is tested, and the number of allergic antibodies in the blood is measured.

Food elimination diet

Usually recommended for people with non-IgE mediated allergies whose symptoms show more slowly.

Food assumed to have caused allergies is withdrawn then gradually re-introduced. If the symptoms appear once the food is re-introduced, it probably suggests an allergy or intolerance.

Food intolerance

Food intolerance means the body cannot properly digest the food you have taken or that particular food irritates the digestive system.

Food intolerance, unlike food allergies, however, does not lead to immediate violent reaction. Its symptoms are usually in one or more body organs and systems.

Food intolerance is also caused by foods that are non-proteins and are more common than allergies.


Symptoms of food intolerance include:

  • Nausea
  • Stomach aches and cramps
  • Diarrhea
  • Irritable bowels
  • A general feeling of the body being unwell

If you are intolerant to specific foods, the symptoms won’t show up almost immediately. Larger amounts are needed before the reaction is triggered. It takes time before the first visible symptoms are noticed.


Several factors lead to food intolerance. However, the most common factor is the absence of enzymes needed to digest specific foods leading to improper or incomplete digestion. The digestive tract not being able to digest certain foods leads to bowel irritations.

Food poisoning in poorly cooked food may also trigger intolerance.

Histamine, mostly in fish, if not well stored, may lead to adverse reactions in susceptible people.

Types of food intolerance

They include:

Gluten, wheat, lactose, caffeine, and other additives.

Notable differences between food allergy and food intolerance are as follows:

  • Food allergy can be potentially life-threatening and may lead to death, but food intolerance cannot be a life-threatening reaction.
  • Food intolerance will cause upsets in the abdominal area and irritable pain in the bowels but will not cause severe anaphylaxis reactions.
  • The amount of food digested will determine whether you are having a food allergy or food intolerance. The reaction happens quickly in allergies, unlike in intolerance, where it takes time.
  • There is no way to know whether one suffers from food intolerance. However, there are allergy tests to determine allergic reactions, and they are reliable to produce accurate results.


Despite the differences, the two, allergies and intolerances, are conditions that should be avoided as they cause pain and discomfort. You should be careful about what foods trigger certain reactions within your body, and consultation with your doctor is highly advised just to be sure. Children are most likely to be affected as they will not be keen on the symptoms.