What is an allergy?
Allergy is a chronic respiratory disease caused by an inappropriate, sudden, undesirable response of the immune system to foreign substances that are normally harmless and don’t provoke disease, such as food, medicines, pollen, insect venom, etc. An allergic reaction occurs when these substances come into contact with various body tissues and generally lead to symptoms in those areas (for example, skin, digestive system, airways, etc.).
How does an allergic reaction work?
The body’s response to allergens is accompanied with the production of specific antibodies called immunoglobulins E. These antibodies activate various cells of the immune system (mast cells in the first place) and cause them to release certain substances (for example, histamine, leukotrienes, and cytokines), which trigger an allergic reaction. E-type antibodies are highly specific for each particular allergen, meaning that some people may, for example, develop an allergy to pollen, while others are allergic to cat hair, milk, eggs, etc. The degree of allergic sensitivity differs across various immunoglobulins, so allergy can manifest itself in different ways: from mild symptoms to serious allergic complications (such as anaphylaxis).