alergene

Alergene is a substance capable of triggering an allergic reaction in individuals who have become sensitized to it. Most allergens are proteins or glycoproteins, though small molecules that act as haptens can also form allergenic complexes. Allergic reactions occur when the immune system produces specific IgE antibodies to the allergen; on re-exposure, the allergen can cross-link these antibodies on mast cells and basophils, releasing mediators such as histamine that cause symptoms ranging from runny nose and hives to life-threatening anaphylaxis.

Common categories of alergene include aeroallergens (pollen, indoor and outdoor molds, house dust mites, animal dander), foods (peanuts, tree nuts, milk, eggs, wheat, soy, fish, shellfish), contact allergens (nickel, fragrance substances, rubber accelerators), and insect venoms (wasp, bee). Sensitization patterns vary among individuals and populations, and some allergens exhibit cross-reactivity with related proteins.

Diagnosis relies on a combination of clinical history and testing, such as skin prick tests or serum-specific IgE measurements. In some cases, supervised oral food challenges are used to confirm or exclude food allergies.

Management focuses on avoidance of known allergens when possible, symptom-relieving medications (antihistamines, nasal or inhaled corticosteroids), and emergency treatment plans that may include epinephrine for severe reactions. Immunotherapy, delivered by injections or sublingual tablets or drops, can reduce sensitivity for certain allergens and may alter the course of the condition for selected patients. Public health measures often promote allergen labeling to help individuals avoid exposure.