What is a house dust mite allergy?

What symptoms can occur in a house dust mite allergy, what diagnosis and therapy look like and what needs to be considered in everyday life

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House dust mite: their droppings cause problems for allergy sufferers

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House dust mite allergy - briefly explained

House dust mite allergy sufferers react to proteins in the feces and bodies of arachnids. These accumulate, for example, on the mattress, but are also found in the dust. A doctor can make the diagnosis based on typical symptoms and allergy tests.

Anyone who suffers from a house dust mite allergy should remove mites as far as possible from their apartment or house. If this does not help enough, allergen immunotherapy (desensitization) is an option. If allergic symptoms persist, antihistamines and nasal sprays with cortisone can help.

What is a house dust mite allergy?

This is usually an allergic reaction to excretions and body debris of the so-called house dust mites. The frequently used term "house dust allergy" is therefore not medically correct. Because the allergy-triggering effect is usually not dust, but protein components from the excrement and the body of the house dust mites that are contained in it.

These tiny creatures are arachnids and can hardly be seen with the naked eye because they are only about 0.1 millimeters in size. In this country it is mostly the species Dermatophagoides pteronyssinus or Dermatophagoides farinae. House dust mites feed primarily on the flakes of skin that humans secrete every day.

House dust mites prefer to stay on mattresses, but also on upholstered furniture or carpets. The bed offers mites the best conditions for survival, as they mainly feed on flakes of skin that humans lose every day. In addition, the arachnids need warmth and a relatively high level of humidity - both of which the sleeper donates involuntarily every night. Since house dust mite allergy sufferers are exposed to the allergenic substance all night, they often have the most severe symptoms in the morning.

Important: Dust mites in bed have nothing to do with poor hygiene. They occur in every apartment. However, certain habits - for example seldom ventilation - and a warm and humid indoor climate can make life easier for the mites.

Sensitive people are allergic to proteins in the faeces and bodies of the mites. These include the allergens "Der p 1" from the faeces, "Der p 2" from the mite body and "Der p 23", a new main allergen from the faeces shell.

The mites and excrement components accumulate on the mattress, but they also get into the house dust and are thus distributed on carpets, floors, curtains and sofas. Every movement that a person makes, when he vacuums or shakes out the pillows, the dust is blown up. The dried material is broken down into fine particles, briefly enters the room air and can be deposited on the mucous membranes in the eyes, nose and deep respiratory tract.

The body's own immune system of allergy sufferers recognizes the allergens and classifies them as dangerous. A house dust mite allergy is a so-called type I allergy. The immune system produces the antibody immunoglobulin E (IgE), which docks with special immune cells, the so-called mast cells.If they are activated, they release messenger substances at the point of action - in this case in the mucous membranes of the respiratory tract, for example nasal or bronchial mucosa. There is an allergic reaction and inflammation with their typical symptoms. Since the body reacts very quickly (within a few minutes) to the allergen with symptoms, type I allergies are also called immediate-type allergies.

How it comes to an allergy to house dust mites is not yet fully understood. Certain mite proteins are probably recognized preferentially by the innate immune system, others penetrate the mucous membrane better than enzymes and thus promote the development of allergies. The basis is, on the one hand, the inherited willingness to suffer from allergies from parents or grandparents. In addition, environmental influences and lifestyle play a role. Studies also indicate that children who have little contact with pathogens and allergens are more prone to allergies later on.

What are the symptoms of a house dust mite allergy?

Many people are allergic to house dust mites without the allergy causing any symptoms. In some of those affected, however, it makes itself felt through typical symptoms. They hardly differ from those caused by hay fever.

However: During the winter months - especially when the heating season starts - people with a house dust mite allergy usually suffer more than in the warm season. The reason: House dust mites multiply during the summer because the conditions are ideal for them. Most of them die in autumn, when the heating season begins and there is low humidity. Their constituents, which have accumulated in large quantities, dry out and are distributed with the house dust via the dry heating air. Hay fever, on the other hand, causes problems especially in spring and summer.

Symptoms of a house dust mite allergy can include, for example:

  • stuffy, runny nose, sneezing attacks (allergic rhinitis)
  • itchy, watery, or red eyes (allergic conjunctivitis)
  • to cough
  • Difficult breathing or wheezing noises
  • in rare cases skin reaction with itching, reddening of the skin and the appearance of wheals

The symptoms mainly occur at night and in the morning because the allergy sufferer is most exposed to the allergens on the mattress while sleeping.

Coughing and breathing difficulties can only occur during or shortly after physical exertion when the airways are additionally burdened. Especially in children, this exertion asthma indicates a house dust mite allergy. It appears shortly after or during intense physical activity and lasts for about half an hour.

But vacuuming or dusting can also trigger the symptoms. This is because dust and allergens are blown into the air and can get onto the mucous membranes. The more mites there are in the apartment, the more violent the allergy can break out.

Chronic complaints with longstanding allergies

Anyone who has suffered from an allergy to house dust mites for many years can develop permanent symptoms. These occur not only in the bedroom at night or in the morning, but also in other places and at other times.

On the one hand, the nasal mucosa and paranasal sinuses can become chronically inflamed due to the permanent exposure to allergens, which can lead to frequent nasal congestion, reduced sleep quality and dull headaches. Sometimes there are also recurring fits of sneezing.

On the other hand, the bronchial mucous membrane can become inflamed. A good third of allergy sufferers gradually develop allergic asthma and general hypersensitivity of the airways. Doctors refer to this as "non-specific bronchial hyperreactivity". The latter manifests itself as an annoying dry cough or can occasionally lead to a tightness in the chest.