Allergeeni

Allergeeni is a substance capable of triggering an allergic reaction in individuals who are sensitized to it. Most allergeenit are proteins or glycoproteins, and they can enter the body through inhalation, ingestion, skin contact, or injection. Allergic reactions occur in people who have developed specific IgE antibodies against the allergeen, leading to a rapid immune response upon exposure.

The underlying mechanism is a type I hypersensitivity reaction. In sensitized people, exposure to an allergeen cross-links IgE antibodies bound to mast cells and basophils, causing these cells to release mediators such as histamine. This mediator release produces symptoms in the affected tissues, which can range from mild irritation to life-threatening anaphylaxis.

Common sources of allergeenit include inhalant allergens such as pollen, house dust mites, mold spores, and animal dander; food allergens such as peanuts, tree nuts, milk, eggs, shellfish, fish, wheat, and soy; insect venoms; and contact allergens like latex or nickel. Some individuals exhibit cross-reactivity, where sensitization to one allergen (for example, a pollen protein) also triggers reactions to related foods (known as oral allergy syndrome in some cases).

Diagnosis typically involves a detailed history and tests such as skin prick testing or measurement of specific IgE antibodies. In some cases, an oral food challenge may be used to confirm a food allergy. Management focuses on avoidance of known allergeenit when possible, symptom-relieving medications (antihistamines, intranasal corticosteroids, inhaled corticosteroids for asthma), and emergency treatment with an epinephrine auto-injector for anaphylaxis. Immunotherapy options, including subcutaneous or sublingual approaches, can reduce sensitivity to certain allergens.