Allergy is when your immune system responds to a substance that you do not expect, develops antibodies specific to it and reacts. These substances are also called allergens. Allergens do not normally cause reactions in humans. However, it can cause reactions in atopic people prone to allergies. Your body does not show this reaction for every substance. Allergens are substances that are usually reacted against. Sometimes, very rare allergic reactions may occur against substances that are not expected to be allergens.

Allergy is when your immune system responds to a substance that you do not expect, develops antibodies specific to it and reacts to it. These substances are also called allergens. Allergens do not normally cause reactions in humans. However, it can cause reactions in atopic people prone to allergies. Your body does not show this reaction for every substance. Allergens are substances that are usually reacted against. Sometimes, very rare allergic reactions may occur against substances that are not expected to be allergens.

Allergens can be taken into our body by inhalation, ingestion, vascular access or skin contact and may cause allergic reactions.

Although low amounts of allergens do not cause serious reactions, they can cause an inflammatory process in the organs. This inflammatory process makes a person hypersensitive to allergens (as in asthma, inflammation of the airways). In other words, they do not develop symptoms when they first encounter them, but they make them overreact to other triggers (chemicals, infections, cigarette smoke, etc.). These stimuli are called triggers. These triggers cause symptoms in organs in an inflammatory process with mildly-acting allergens. While allergens are responsible for both a trigger and an inflammatory process, some triggers can cause a chronic inflammatory process.



To date, 1091 substances have been registered as allergens because they cause an allergic reaction in the human body. Allergens are divided into two according to the official records made by the Allergen Nomenclature Subcommittee of the World Health Organization and the International Union of Immunological Societies (WHO/IUIS):

  • Inhaled allergens
  • Non-respiratory allergens

What are inhaled allergens?

  • Pollen
  • Caused by mites
  • Originating from mammals
  • Caused by insects
  • Fungal spores
  • Caused by algae

What are non-respiratory allergens?

  • Food allergens
  • Insect allergens
  • Mrug allergens
  • Contact allergens
  • Other allergens

What are the triggers?

  • Stress
  • Cigarette smoke
  • Exercise
  • Infections
  • Air pollution

The most common allergen agents in the world are pollen. Pollen is 30% common among all allergens. Similarly, fungal spores come in second place with a frequency of 10%. Then mites and food allergens are monitored. Planes and fungal spores can cause discomfort in the nose, eyes and lungs as allergens are spread by wind current. Other allergens, on the other hand, cause more frequent reactions in the areas where they come into contact with the body.

You can read detailed information about allergens in our articles about each allergen.

How can we protect ourselves from allergens?

Exposure to allergens can be reduced by taking precautions according to the cause of allergic reactions. Environmental precautions are important in this regard. We can list these measures step by step as follows:

  • Allergy assessment and tests for the patient
  • Detection and measurement of allergens in the environment
  • Humidity control
  • Cleaning and using protective covers
  • Regular sweeping and vacuuming
  • Vacuuming and washing pets
  • Using an air filter
  • Integrated pest management
  • Preventing pest migrations
  • Keeping foods covered
  • Fighting dampness and mold