Allergy, or sensitisation, consists of an excessive, abnormal reaction of the immune system to substances in the environment that are foreign to the body, known as allergens, which it should normally ignore.

In healthy people, these substances do not cause any discomfort, but in allergic people they cause a range of unpleasant and sometimes even dangerous reactions. Allergic diseases are widespread. In developed countries, various types of allergy affect approximately 30% of the population.

Allergy symptoms can occur at any age. However, a certain correlation can be shown between age and the type of disease. Food allergies most often manifest themselves in infancy. Hay fever, allergic conjunctivitis and atopic asthma in children and adolescents. Urticaria and sensitisation to hymenopterous insect venoms in adults.