Dust allergy is an allergic reaction that occurs upon contact with components of street or house dust and manifests itself in the development of symptoms of rhinitis, conjunctivitis, atopic dermatitis or bronchial asthma. Diagnostics includes anamnesis collection, physical medical examination, general clinical and allergological studies (skin scarification tests, identification of specific immunoglobulins). Therapeutic measures provide for the termination or reduction of contacts with the allergen, taking antihistamines, symptomatic agents, conducting ASIT.
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Dust allergy is a hypersensitivity reaction that develops when foreign protein components contained in dust enter the respiratory tract or on the skin. Clinical symptoms are manifested by the development of a runny nose, cough and sneezing attacks, difficulty breathing and suffocation, itching of the skin. According to WHO, approximately 40% of all cases of year-round allergic reactions on Earth are associated with an increased sensitivity of the body to dust components. The most common allergen present in household dust is microparticles of mites and their waste products. On average, one gram of dust from a mattress can contain from 200 to 15,000 mites.
The complex of organic and inorganic components contained in dust includes all kinds of chemicals that enter the apartment from the street, fragments of animal life, insects, arachnids and other potential allergens:
- Street dust. It contains particles of soil, gravel, bitumen, cement, soot, pollen of plants and fungal spores, various microorganisms.
- Animal waste products. These are wool, dandruff, saliva, sebaceous gland products, excrement of domestic animals (cats, dogs, rabbits, guinea pigs, etc.). The main allergenic properties are foreign proteins of saliva and the upper layer of animal skin attached to their wool.
- House dust mites. Microscopic fragments of bodies and excrements of pyroglyphid mites of house dust are localized in mattresses, blankets, pillows, carpets and upholstered furniture upholstery. Ticks feed on constantly exfoliating cells of the human epidermis, releasing special enzymes for their cleavage, which are strong allergens. The optimal environment for the vital activity of pyroglyph mites is humidity above 50-60% and temperature in the range of 20-26 degrees Celsius.
- Other allergens. They include cellulose particles from paper pages of books and various microorganisms contained in library dust, mold fungi, fragments of insect bodies and secretions (flies, ants, cockroaches).
The above allergens are microscopic in size, volatile, water-soluble, so they can easily enter the human body together with dust in direct contact with interior items and bedding (during sleep and rest, when cleaning rooms), and by inhalation.
During initial contact with dust allergens, sensitization develops, accompanied by increased production of specific IgE immunoglobulins by immune cells. Repeated penetration of a foreign protein into the body (on the mucous membranes of the nasopharynx, bronchi, skin) and its interaction with antibodies causes activation of mast cells with the release of inflammatory mediators and the development of clinical manifestations of an allergic reaction in one of the “target organs”. The corresponding symptoms may appear in the first minutes after interaction with the allergen (in the early phase) or after 3-6 hours (delayed phase). In pathogenesis, there is also a mechanism of nonspecific tissue hyperreactivity to substances that are not true allergens. At the same time, symptoms appear in response to the nonspecific irritating effect of non-protein dust components in the absence of an immunological stage and the development of the inflammatory process by the mechanism of a pseudoallergic reaction.
Symptoms of dust allergy
The clinical picture of an allergic reaction to dust depends on the path of penetration of foreign proteins into the body (mucous membrane of the nasopharynx, larynx and bronchi, skin), hereditary predisposition, age, concomitant diseases and other factors. At the same time, signs of conjunctivitis, rhinitis, bronchial asthma, atopic dermatitis appear. Symptoms of dust allergy can be observed all year round, including in the autumn-winter period.
Clinical manifestations of allergic conjunctivitis are characterized by damage to the conjunctiva with its redness and expansion of capillaries, the appearance of hyperemia and swelling of the edges of the eyelids, lacrimation. In the acute period, symptoms develop in the first minutes or hours after the allergen hits the conjunctiva and is accompanied by intense itching, burning sensation under the eyelids, photophobia. When allergic to dust, a chronic course of conjunctivitis with scanty manifestations is more common: periodic itching and burning in the eye area, slight lacrimation.
Irritation of the nasal mucosa with allergic rhinitis is manifested by sneezing attacks, which become more pronounced in the evening after entering a dusty room, as well as after a night’s sleep. Sneezing is accompanied by copious rhinorrhea and itching. With chronic sensitization, there is a periodic feeling of itching, tickling in the nasal cavity, full nasal breathing is difficult. At night, there is a tickling in the throat and a superficial cough caused by irritation of the nasopharynx by the flowing mucous contents of the nasal cavity.
Allergic inflammation of the mucous membrane of the bronchial tree leads to shortness of breath, a feeling of lack of air, dry cough with difficult-to-separate sputum, sudden attacks of obstruction with suffocation. Exacerbation of atopic bronchial asthma caused by dust allergy is more often observed in autumn and winter due to an increase in the amount of dust in the premises and a decrease in air humidity during the heating season. At the same time, the patients’ well-being improves significantly after leaving the dusty premises in the morning, and worsens in the evening after returning to the apartment.
The lesion of the skin with allergies to dust is characterized by the presence of itchy rashes on the skin by the type of urticaria, signs of atopic dermatitis with persistent erythema and peeling, the appearance of cracks, eroded areas with wetness and subsequent formation of crusts, frequent infection of damaged surfaces. Skin itching becomes one of the main symptoms of allergic dermatitis, intensifying during room cleaning and at night. The general condition of patients is often disturbed, which is manifested by frequent headache, sleep disorders, irritability and mood fluctuations, social maladaptation.
The complicated course develops with frequent exacerbations of respiratory and skin allergoses, the addition of bacterial infection, a combination of dust allergy with chronic respiratory diseases. After 3-5 years of moderate atopic asthma, emphysema of the lungs and pulmonary heart may develop. Systematic contact with industrial dust is fraught with the occurrence of pneumoconiosis. Occasionally, dust allergy can cause systemic disorders: thrombocytopenic purpura, exogenous allergic alveolitis, nephropathy.
For the correct diagnosis of dust allergy, it is necessary to carefully collect an allergological history (the presence of a hereditary predisposition, previous allergic reactions, deterioration of well-being in closed rooms with an abundance of upholstered furniture and carpets, while cleaning rooms). At an appointment with an allergist-immunologist, a clinical examination of the skin and visible mucous membranes, palpation of internal organs is performed, general clinical and biochemical analyses, spirometry are prescribed. In the presence of allergic inflammation of the nasopharynx, skin, an ENT doctor, dermatologist, ophthalmologist is consulted.
To detect the disease, skin scarification and prick tests are performed with standard epidermal allergens of animals (cats, dogs, sheep, rabbit) and house dust mites, specific IgE immunoglobulins are determined. According to the indications, provocative tests can be performed. Differential diagnosis of dust allergy is carried out with other allergic diseases, pathology of ENT organs (rhinitis, sinusitis of viral and bacterial etiology), acute and chronic bronchitis, skin diseases.
Treatment of dust allergy
Therapeutic measures include limiting contact with allergens, the use of barrier drugs, anti-allergic agents, ASIT.
- Reducing contact with dust. Carrying out regular wet cleaning of premises (floors and walls, furniture and household appliances) with cleaning of carpets, mattresses, timely replacement of bed linen. It is advisable to replace feather pillows and duvets with synthetic ones. It is necessary to ventilate the rooms daily, humidify the air in the rooms.
- Barrier means. In the initial stage of allergic rhinitis caused by dust allergy, it is possible to use special sprays applied to the nasal mucosa and creating a barrier, protective layer there that prevents the penetration of the allergen.
- Anti-allergic agents. Antihistamines of the first and second generation, membrane stabilizers are used, in severe cases – glucocorticosteroids topically, orally or parenterally.
- ASIT. The use of allergen-specific immunotherapy is most effective in allergic rhinitis and bronchial asthma (if allergens of pets and dust mites are detected during immunological examination). Treatment should be carried out according to strict indications, taking into account possible side effects from therapy. The total duration of ASIT is from 2 to 5 years.
Prognosis and prevention
Timely detection of allergens that caused a hypersensitivity reaction in contact with dust and the appointment of adequate treatment (including immunotherapy), allows to achieve a stable remission of the disease. Severe and complicated forms with disability develop with systematic exposure to dust irritants (household, library, industrial dust). The prevention of exacerbations is based on the constant implementation of measures to reduce contact with dust: daily wet cleaning of the apartment, hygienic treatment of pets, automation of technological processes, the use of personal protective equipment (respirators, masks).