Allergy to dust mites

The subject of allergies and all the associated health problems are becoming increasingly important, especially in industrialised countries: one of the reasons for this is the high demands placed on the quality of life. People insulate their houses and apartments, electrically controlled heating systems ensure an even room temperature, air conditioning systems take care of the appropriate room climate and comfortable upholstered furniture creates the ideal conditions for feeling good. But most people forget that these ideal conditions also create a cosy home for less welcome permanent guests: House dust mites. People with allergic asthma in particular are increasingly struggling with respiratory diseases in their cosy living environment with high humidity and well-heated rooms. The reason for this is their co-inhabitants, who really appreciate the warm and humid room climate.

For example, house dust mites live in every household that is located at an altitude of up to 1,500 m above sea level. Contrary to the assumption that the microscopically small animals are the direct triggers of a house dust mite allergy, the tiny protein-containing excrement balls of the mites are the actual cause of the allergy. They mix with the house dust and get into the mucous membranes of the eyes and the respiratory tract or come into direct contact with the skin - some people react to the proteins in these excrement balls with hypersensitivity.

Optimal living conditions for house dust mites are temperatures of 25 to 30 degrees as well as a high air humidity between 65 and 80 percent. For this reason, house dust mites particularly like to populate bed mattresses: Enough food in the form of human skin flakes as well as fungi and a humid warmth are guaranteed here. Thousands of mites can live in a bed per gram of dust. Since humans spend about a third of the day in bed, there are plenty of opportunities to come into contact with the mites' allergens.

As already mentioned, the excrement of house dust mites contains a lot of protein. If you inhale these proteins, antibodies (defence substances) are formed by the body; these are, among other things, the cause for the release of histamine. Histamine is the most important inflammatory substance, which is responsible for the development of allergic symptoms or, for example, for reddening of the skin, swelling, leakage of fluid from the blood vessels or constriction of the airways.

Now, unfortunately, dust mites are present in the human environment throughout the year, while pollen, for example, is seasonal. For this reason, allergy to dust mites is also called year-round allergy or perennial allergy. In addition, pets promote a proliferation of mites, as they also provide humidity in the human environment.

In every apartment there is house dust, which contains mite droppings - this leads to sometimes severe allergic reactions in certain people. For those affected, the symptoms are usually noticeable throughout the year - the cycle of reproduction of the mite. Especially during the transitional periods (autumn/winter, winter/spring) symptoms occur more frequently. Mostly the eyes, nose and respiratory tract are affected, but the skin also shows allergic reactions.

Most common symptoms:

• blocked or runny nose
• sneezing
• red, itchy, watery eyes
• increased sensitivity to light
• conjunctivitis
• respiratory distress, bronchial asthma
• hives
• in children: Exacerbation of eczema

As a rule, the symptoms intensify at night or in the morning after getting up, as well as when making the bed. The maximum of complaints is typically reached in warm and humid weather - i.e. towards the end or at the beginning of the heating season.

As a person affected, it is usually sufficient to tell the doctor when and where the symptoms occur and, above all, what they look like. With the help of skin tests - for example, the prick test - or blood tests (to determine the antibodies), the doctor can then make or confirm the diagnosis.

If one suffers from an allergy to house dust mites, everything should be done to make the living conditions for the little co-inhabitants as unparadisiacal as possible or to keep their numbers as low as possible. However, it is hardly feasible to completely remove house dust mites from the household. However, the following measures will help:

• Provide mattress and bedding with mite-impermeable covers.
• Replace mattresses that have been in use for more than eight years.
• Wash all bedding (including upholstery and blankets) regularly at at least 60 degrees, this kills the mites.
• Furnish rooms with as little upholstered furniture as possible, especially in the bedroom.
• Remove dust catchers - such as stuffed animals, cushions, dried flowers etc. - from the room. - Remove them.
• Use carpets that can be washed weekly.
• If possible, do not use carpets or curtains at all.
• Clean wooden furniture, woodwork, walls and floors with damp cloths.
• Daily airing is necessary, do not use humidifiers. Heat bedrooms only a little or not at all.
• Keep pets out of the bedroom.
• Avoid smoking in the house.
• Use a humidity meter.
• Clean carpets, rugs and upholstered furniture regularly and treat them at least every three months with "acaricidal agents" (from the pharmacy).
• Prefer vacuum cleaners with special water or fine dust filters, do not keep filter bags in the appliance for longer than two to three weeks.

Medicinal treatment is also advisable in many cases; the following medicines help to alleviate symptoms:

• antihistamines (tablets, drops, spray)
• decongestant nose drops (max. ten days)
• anti-allergic eye drops cortisone (tablets, spray)
• mast cell stabilizers (cromoglicic acid)
• Beta-sympathomimetics (especially short-acting)

If there is no improvement despite all the above measures and despite drug treatment and the allergic reactions remain, a "vaccination cure" (hyposensitization) should be considered. In the course of this "cure", the allergen is injected directly under the skin in increasing concentrations over a period of several years (at least 3) - with the aim of getting used to the allergen. The disadvantage of this is that no anti-allergic medication may be used during the entire hyposensitisation period. Incidentally, the success rate is 70 percent, but much higher in younger patients.

With regard to allergic rhinitis, treatment is definitely necessary to prevent the development of asthma. With allergic bronchial asthma, one should regularly go to the lung specialist for control or treatment, so that it does not come to chronic late consequences.