Olga Antigoni Papagiannopoulou MD, MSc, Allergist, Thessaloniki

Olga Antigoni Papagiannopoulou
MD, MSc - Pediatric Allergist & Adult Allergist


	What is Allergy? Allergy (from the Greek words “allos” meaning other and “ergon” meaning reaction) is a different, unexpected reaction of the immune system. It is a condition characterized by an excessive and inappropriate response of the body to harmless substances known as allergens. In non-allergic individuals, these allergens do not cause any reaction.


	Facts About Allergy

	Allergy usually appears in childhood and may persist for years or even a lifetime. However, it can occur at any age. Allergic diseases are among the most common chronic conditions in children and young adults in Europe. In children, it is common for one allergic condition to be followed by another (known as the “allergic march”). Atopic dermatitis often appears first, affecting more than 10% of infants in Europe. Although allergies often have a genetic predisposition, many new cases occur in individuals without a family history. Asthma and allergic rhinitis or conjunctivitis often coexist and are treated as a unified allergic condition of the respiratory system.



	Causes of Allergy Allergy is caused by a dysfunction of the immune system, which is responsible for the body's defense. The immune system protects the body by activating defense mechanisms when it detects harmful external factors (e.g. viruses, bacteria) or abnormal cells (e.g. cancer cells). When substances entering the body are harmless, the immune system recognizes them as safe and does not react. In allergic individuals, however, the immune system malfunctions and overreacts to these harmless substances, causing an allergic reaction.

Allergic Diseases

The most common allergic diseases include allergic rhinitis, conjunctivitis, bronchial asthma, atopic dermatitis (eczema), and urticaria. These conditions represent a significant public health issue and are expected to increase in the coming years.
Allergic patients have a genetic predisposition that makes them more sensitive to certain substances, even during periods when no previous reactions were observed.
The main allergens include pollen, house dust mites, animal dander, fungi, foods, insect stings, medications, and chemicals.
An allergic reaction is an exaggerated response that occurs after exposure to the same allergen, accompanied by inflammatory processes and symptoms.
Allergies are treated with antiallergic and antihistamine medications that relieve symptoms but do not provide a complete cure.
The most effective long-term solution is immunotherapy (vaccines), which reduces or even eliminates the symptoms of allergic reactions.