allerjen

Allerjen, often rendered as allergen in English, is any substance capable of triggering an allergic reaction in individuals who are predisposed. Most allerjen are proteins or glycoproteins, though some small molecules can become allergenic when bound to a larger carrier protein. When first exposed, a person may become sensitized and produce allergen-specific IgE antibodies. On subsequent exposure, the allerjen can bind to IgE on mast cells and basophils, causing these cells to release mediators such as histamine. This immune activation leads to symptoms ranging from nasal congestion and itching to hives, wheezing, or, in severe cases, anaphylaxis.

Allerjen are often categorized by source. Common environmental allerjen include pollen from trees, grasses, and weeds; mold spores; dust mites; and pet dander. Food allerjen cover items such as peanuts, tree nuts, milk, eggs, fish, shellfish, wheat, and soy. Other important categories are medications (for example beta-lactam antibiotics), latex, and insect venoms. Cross-reactivity can occur when related allerjen share similar protein structures, causing reactions to multiple substances.

Diagnosis typically relies on clinical history supported by tests such as skin prick testing or serum-specific IgE measurements; oral or nasal challenges may be used under supervision for certain foods or medicines. Management focuses on avoidance of known allerjen and on symptom control with medications such as antihistamines, intranasal corticosteroids, inhaled bronchodilators, or, in emergencies, epinephrine. Allergen immunotherapy, via injections or sublingual tablets, can reduce sensitivity for selected allerjen, particularly pollen, dust mite, and venom allergens.