What are the causes of allergies?

Allergic diseases are among the most common chronic diseases. Experts estimate that 30%-40% of the population worldwide suffer from one or more allergic diseases.

At present, there are an estimated 10 million people with allergies in Spain.

Main allergens that cause allergies

There is a certain amount of age-related variability. For example, food allergies and dermatitis are more common in the paediatric population, and as children grow they experience the onset of different respiratory problems: Rhinitis and Asthma. This process has come to be called the“Allergic March”.

The peak incidence of allergies is at 14-24 years of age.

In Spain, the most common food allergies are to cow’s milk, eggs, fish and nuts. In many children, food allergies are transitory and disappear when patients grow.

As regards inhaled allergens, there are so-called indoor allergens, which are typically  mites; the animal dander ; and, to a lesser extent, fungi and outdoor allergens, which are basically pollen and fungal spores.

In general, individuals develop allergies to the allergens to which they are most exposed. This is particularly notable in pollen. Pollen allergies depend on the pollen present in the geographic area of patients with allergies.

Why the prevalence of allergies is increasing

In general, there are two essential factors in developing an allergic disease: genetic load and environmental exposure.

In recent years, allergic diseases have had a considerable increase that cannot be explained by genetic changes, which occur very slowly. Therefore, environmental factors would be responsible for developing allergic diseases.

Other reasons are:

  • The increase in environmental pollution is another potential reason for the increase in allergic diseases, since some pollutants such as diesel emissions are believed to increase the potential for sensitisation.
  • The Lifestylealso plays a role, since the population is being exposed for longer periods of time at home to contaminants such as cigarette smoke and allergens such as mites.
  • Non-exposure to infectious agents and antibiotic treatment. The immune system fails to mature due to a lack of stimulation, and instead allergic and autoimmune diseases develop.

Any natural substance may cause allergic diseases through inhalation, ingestion or contact. Such a substance is called an allergen.

But what substances cause allergies?

Any natural substance may cause allergies in the body. Such a substance is called an allergen, and the main agents that cause the allergic process are:

MITES: These are microscopic "bugs" that live in homes and are found in household dust and on the surfaces of objects. They feed on our dead cells and any type of environmental proteins, and cause allergic reactions in a high percentage of the population.

POLLEN: These are microscopic grains found in the flowers of plants. They spread through the air and cause allergic reactions when inhaled. The most common are:

  • -Grass Pollen
  • -Plant Pollen
  • -Tree Pollen

FUNGI: These are a group of living beings that develop on any surface and reproduce by means of spores, which mainly spread by the wind and which cause approximately 10% of cases of asthma of allergic origin.

FOODS: Any food or condiment may end up triggering an allergic reaction. The most common foods are: Milk, eggs, fish, seafood, nuts and fruits.

HYMENOPTERA VENOM: The main causes of allergies due to stings are bees and wasps. These may cause reactions such as swelling and itching and may trigger serious reactions and in some cases anaphylaxis.

ANIMAL DANDER:The substances present in the fur of certain animals may end up causing allergies. Cats, dogs and horses are among the most allergenic animals.

DRUGS: Any drug can cause an allergy. Taking drugs suspected of causing allergies must be avoided, and the specialist must be informed of the supposed reaction triggered to start an allergological study.

Pollen, mites, fungi, foods, hymenoptera venoms, dander and drugs are substances that may cause an allergic reaction.


Your personal data will be processed by Diater Laboratorio de Diagnóstico y Aplicaciones Terapéuticas, S.A. for the purpose of responding to the questions raised by the User through this channel. You may exercise your rights of access, rectification, deletion, portability, limitation, opposition and the right not to be subject to automated individual decisions. For more information, please consult our Privacy Policy.

security image


914 96 60 13
This email address is being protected from spambots. You need JavaScript enabled to view it.
Share This
Follow Us