What causes allergy to dust mites? - briefly
Allergic reactions to dust mites arise from proteins in their feces, body fragments, and saliva that trigger an IgE‑mediated immune response. High indoor humidity and accumulation of dust increase exposure to these allergens, leading to sensitization and symptoms.
What causes allergy to dust mites? - in detail
Dust‑mite allergy results from an immune reaction to specific proteins found in the feces, body fragments, and secretions of Dermatophagoides species. When these microscopic particles become airborne and are inhaled, they encounter the mucosal lining of the respiratory tract. In susceptible individuals, antigen‑presenting cells process the proteins and present them to T‑lymphocytes, prompting the production of allergen‑specific IgE antibodies. Subsequent exposure triggers IgE binding to mast cells and basophils, leading to degranulation and release of histamine, leukotrienes, and cytokines that generate classic allergic symptoms such as sneezing, nasal congestion, itchy eyes, and asthma exacerbations.
Key allergenic components include Der p 1, Der p 2, Der f 1, and Der f 2, which possess enzymatic activity that disrupts epithelial barriers and enhances immune activation. The potency of these proteins varies among mite species and environmental conditions, influencing the severity of reactions.
Several factors amplify the likelihood of sensitization:
- Genetic predisposition: Family history of atopy increases IgE‑mediated responses.
- Environmental humidity: Relative humidity above 50 % supports mite proliferation and fecal particle dispersion.
- Indoor reservoirs: Bedding, upholstered furniture, carpets, and curtains retain moisture and provide habitats for colonies.
- Ventilation quality: Poor air exchange concentrates allergen load.
- Cleaning practices: Infrequent washing of linens or use of ineffective cleaning agents allows accumulation of mite debris.
Preventive measures focus on reducing exposure to the allergenic particles. Strategies include maintaining indoor humidity below 45 %, washing bedding weekly at temperatures ≥ 60 °C, encasing mattresses and pillows in allergen‑impermeable covers, employing high‑efficiency particulate air (HEPA) filters, and removing or regularly cleaning carpeted areas. For individuals already sensitized, pharmacologic interventions such as antihistamines, intranasal corticosteroids, or immunotherapy target the downstream inflammatory cascade.
Understanding the biochemical nature of dust‑mite allergens, the immune mechanisms they provoke, and the environmental conditions that favor their presence provides a comprehensive explanation of why certain people develop hypersensitivity to these ubiquitous arthropods.