Symptoms
A dust mite allergy manifests itself in allergic symptoms. These include:
- Perennial allergic rhinitis: sneezing, runny nose, in the later course of the disease rather a chronically stuffy nose.
- Allergic conjunctivitis: itchy, watery, swollen and red eyes.
- Sinusitis with headache and facial pain
- Lower respiratory tract: cough, bronchial asthma.
- Itching, rash, eczema, exacerbation of atopic dermatitis.
Symptoms may become chronic and may later occur regardless of allergen exposure due to the inflammatory response.
Causes
The cause of the disease is an allergic reaction against the excretions of dust mites, especially from and . The dead bodies of the mites can also trigger the allergy. The mites feed on dead skin scales and can be found in beds, mattresses, pillows, blankets, carpets, armchairs and sofas, among other places. They are arachnids with eight legs – not insects! – which, with a size of about 300 µm, are so small that they remain invisible without a microscope. House dust mites multiply mainly in a humid and warm environment. They need sufficient humidity because they do not drink, but absorb the water with their bodies. The bed is usually heavily polluted, because there is high humidity and a lot of dander is found there. Unlike scabies mites, house dust mites are not parasitic and do not burrow into the skin of humans. The triggering allergens are mainly digestive enzymes of the mites.
Diagnosis
The diagnosis is made in medical treatment on the basis of the patient’s history, clinical symptoms, physical examination, with a skin test, an antibody test in the blood and possibly with a provocation test. Other allergies must be excluded. In contrast to seasonal hay fever, house dust mite allergy occurs throughout the year. Antibody tests are also offered as self-tests.
Nonpharmacologic treatment
The following measures are intended to reduce the number and reproduction of mites:
- Special mite allergen-proof covers are recommended for mattresses, pillows and blankets.
- Wash the bed and pillow covers and soft toys every week hot (>60 ° C).
- Remove the house dust by damp pick-up, cleaning and vacuuming with a HEPA filter.
- Keep humidity low (between 30 to 45%) and room temperature low (18-21°C).
- Clean the air with a HEPA air purifier.
- Furnish the rooms with only a few indoor plants.
- Sofas and armchairs with leather instead of fabric covers.
- Replace carpeting if possible, for example, with parquet, vinyl or cork.
- Refrain from pets with fur or feathers (animal dander).
- Regularly ventilate, remove unnecessary dust traps.
- Use of a steam cleaner.
- Wearing a respirator mask at increased exposure, for example, when changing bed linen or vacuuming.
- Mite sprays with acaricides to kill the mites.
- In mountainous areas (> 1200 m) there are few mites because they reproduce poorly.
Drug treatment
Causal treatment is possible with immunotherapy (hypo / desensitization). In this case, the allergens are administered subcutaneously or sublingually. Immunotherapy can bring about a complete or partial cure. Various antiallergic drugs are available for acute drug treatment:
- Glucocorticoids have antiallergic, anti-inflammatory, and immunosuppressive properties and are commercially available as nasal sprays, inhalers, and eye drops, among others.
- Antihistamines, such as loratadine, cetirizine, or fexofenadine, for example, reverse the effects of histamine, which is involved in triggering symptoms. They are commercially available as tablets, as eye drops, nasal sprays and gels, among others.
- Mast cell stabilizers such as cromoglicic acid and ketotifen inhibit the release of inflammatory mediators.
Antiasthmatics:
- Beta2-sympathomimetics are administered as inhalation, dilate the bronchi and facilitate breathing in asthmatic symptoms.
- Leukotriene antagonists such as montelukast are approved for the treatment of allergic rhinitis in addition to asthma. They cancel the effects of pro-inflammatory leukotrienes.
