Why are some people allergic to pollen?

Each spring, millions suffer due to pollen. This fine dust produced by plants causes seasonal allergies in some individuals. But why?

The allergic reaction

Pollen allergy, or seasonal allergic rhinitis, is an overreaction of the immune system. Typically, this system protects against harmful invaders like bacteria and viruses. In allergic individuals, this system also reacts to harmless substances like pollen.


When pollen comes into contact with the mucous membranes of the eyes, nose, or airways, the immune system produces antibodies called immunoglobulins E (IgE). These antibodies attach to specific cells called mast cells.

Upon subsequent exposure to pollen, the IgE recognizes the pollen and triggers the release of chemicals such as histamine, causing allergic symptoms like sneezing, itching, watery eyes, and nasal congestion.

Genetic and environmental factors

The tendency to develop allergies is often hereditary. If one or both parents are allergic, there is a high probability that their children will be as well.

However, environmental factors also play a crucial role. A late introduction to and reduced exposure to allergens during childhood can increase the risk of developing allergies later. Additionally, decreased exposure to microbes due to increased hygiene may contribute to the rise in allergies.

This hypothesis, known as the hygiene hypothesis, suggests that the less the immune system is exposed to actual pathogens, the more likely it is to overreact to harmless substances like pollen.

Diagnosis and treatment

Diagnosis of pollen allergy is typically done through skin tests or blood tests performed by an allergist. Treatments include antihistamines, decongestants, and nasal corticosteroids. Immunotherapy, which involves gradually exposing the person to increasing doses of the allergen, can also be considered to reduce sensitivity.