In the case of house dust allergy, the immune system reacts hypersensitively to certain substances in the faeces of house dust mites. Symptoms such as watery, itchy eyes, runny nose, coughing and skin reactions occur. The allergy can trigger shortness of breath and allergic asthma. Read more about treatment and diagnosis here and find out what to do if you have a dust mite allergy.
House dust allergy ICD codes: J45 | J30
- Symptoms: The symptoms of house dust allergy include reddened, watery eyes as well as a runny nose, coughing and possibly asthma with acute shortness of breath.
- Treatment: In order to alleviate the discomfort, it is recommended to reduce the mite load in one’s own home. In addition, hyposensitization and medication against the symptoms are available.
- Causes and risk factors: A house dust allergy is caused by a dysregulation of the immune system. Factors that favor an allergy include smoking and air pollution.
- Prevention: In the case of an existing house dust allergy, measures such as reducing the mite load help to prevent allergic symptoms.
- Course of the disease and prognosis: With consistent treatment, the symptoms can be reduced or completely eliminated. Over time, however, a house dust allergy may develop into allergic asthma (change of floor).
- Diagnosis: Allergy and blood tests, among other things, are available for diagnosing house dust allergies.
What is a house dust allergy?
The house dust allergy is triggered by certain proteins of the house dust mite. These proteins are mainly found in the faeces, but also in the bodies of the small arachnids. It is therefore correctly called house dust mite allergy.
Colloquially, the disease is also called dust allergy and mite allergy. It usually develops in childhood and adolescence and usually lasts for life.
The house dust mites themselves are harmless because they do not suck, sting or bite and do not transmit diseases. They are not visible to the naked eye and can generally be found in every home, in fact – as their name suggests – in house dust.
They feed mainly on human dander. That is why they prefer to cavort in upholstered furniture, pillows, beds and carpets. The mites feel most comfortable at a room temperature of 25 degrees and a humidity of 65 to 80 percent.
House dust mite allergy is one of the most common forms of allergy in Europe.
What are the symptoms?
The messenger histamine sets the house dust allergy symptoms in motion. This is released in large quantities through contact with certain proteins of the mites:
It causes the mucous membranes to swell, widens the blood vessels, stimulates mucus production and is involved in inflammatory processes. As a result, with a house dust allergy, symptoms develop in the area of the eyes and nose as well as in the respiratory tract and on the skin :
- Red, itchy and watery eyes are typical symptoms of house dust allergy. Contact with the allergen triggers conjunctivitis (allergic conjunctivitis).
- The nose is often blocked because the mucous membranes swell and secretion is increased. A runny nose and the urge to sneeze may also occur.
- Under certain circumstances, the house dust allergy leads to a mucous cough (bronchitis) and even to allergic asthma with acute shortness of breath.
- On the skin, a house dust allergy can cause symptoms such as itching, rashes and hives. Hives (urticaria) form wheals – small, red swellings – on the skin.
- Another possible symptom of dust mite allergy is fatigue.
All the symptoms of a dust mite allergy may also show up in other allergies and other diseases. Symptoms such as a runny nose and cough may be misinterpreted as signs of a simple cold. Therefore, a house dust allergy is often recognized late or not at all.
When do the house dust allergy symptoms appear?
House dust allergy symptoms occur all year round because house dust mites live permanently in living spaces. In late autumn and winter, the symptoms are usually particularly pronounced.
The small arachnids reproduce mainly between May and October. When the air humidity in the rooms drops in late autumn due to the heating air, the mites die off in large numbers because they need a damper environment.
The dead mites and their excreted feces break down, mix with the house dust and are then inhaled with the air. Signs of a house dust allergy therefore appear more frequently in these months than in the rest of the year – especially if the room is also seldom aired, as is often the case in winter.
During the course of the day, the house dust allergy symptoms are particularly noticeable at night or in the morning after getting up. Mattresses are considered to be the largest mite reservoir.
The house dust mixed with dead mites and mite droppings is easily stirred up and then inhaled during activities such as making the bed, dusting and vacuuming. The house dust mite allergy symptoms are therefore often particularly noticeable during daily housework.
Because the symptoms of a house dust allergy appear suddenly or very quickly after contact of the mucous membranes with the allergen, the disease is one of the immediate type (type I) allergies.
The mite proteins that trigger a house dust mite allergy are similar to proteins in crustaceans. This is why some house dust allergy sufferers are hypersensitive to shrimp, crabs and lobsters, for example – eating these animal foods may trigger allergy symptoms in those affected.
In such a case, physicians speak of a cross-allergy.
What to do if you have a house dust allergy?
The treatment of house dust allergies consists above all in reducing the mite load in the living rooms. In addition, the symptoms can be alleviated with various medications against a house dust allergy.
Hyposensitization is recommended against the house dust allergy cause – the oversensitive immune system.
Reduced mite burden
In the case of a house dust allergy, it is very important to keep the dust mite load low in your own home. The following tips will help:
Place as little upholstered furniture as possible in your home , as these serve as ideal dust collectors. A better alternative here are, for example, leather fittings. Avoid other dust collectors, such as carpets, pillows, stuffed animals, heavy drapes, and open bookshelves, if possible.
Ideally, vacuum existing upholstered furniture and carpets thoroughly once a day. If you are affected by a house dust allergy, a vacuum cleaner with a special fine dust filter (Hepa filter) is particularly suitable. Despite this special filter, it makes sense for people who are allergic to house dust to leave the vacuuming to someone who is not overly sensitive to house dust mites.
Choose curtains made of washable materials and clean them every six months.
When cleaning the apartment, preferably use damp dusters and wipe the floors with a damp cloth . This way less dust is stirred up.
Get a mite-proof mattress protector. It is important that such an encasing cover completely encloses the mattress and that you wash it about every three months. If you use such a mite protection, it does not matter what material the mattress itself is made of. However, a filling made of horsehair is unfavorable: the allergens in the animal hair may put additional strain on the immune system in the event of a house dust allergy.
If you have a house dust allergy, it is best to use bed linen (covers) made of cotton. Frequent changing of bed linen is also recommended if you have a dust mite allergy. Wash them once a week at at least 60 degrees. Bedding (blankets and pillows) should be washed at 60 degrees or more at least every three months.
By wearing pajamas at night , you may prevent dander from getting into bed. There are now detergents with mite-killing (acaricidal) substances. This means that mites can be killed even at washing temperatures below 60 degrees. How effective such acaricidal substances are in practice cannot be said unequivocally: the corresponding study results are contradictory.
If your child has a house dust allergy and doesn’t want to be without their cuddly toy, wash them regularly at at least 60 degrees. If it doesn’t need to be washed that hot, freeze it regularly for 12 hours and then wash at a lower temperature: the cold will kill the mites, washing will remove them.
To reduce humidity, ventilate living areas daily (for five to 15 minutes), especially bedrooms.
If possible, avoid putting potted plants in your home, especially in the bedroom. They increase the humidity, which means that dust mites and mold (which the mites also feed on) thrive better. Mold also likes to grow on potting soil.
Holiday tips: If possible, look for a hotel that offers allergy-free rooms. If you suffer from a severe house dust allergy, take your mattress encasing with you as a precaution. If there is no special room for people with allergies, remove as many plush things as possible and ventilate the room well. By the way: in regions above 1,500 meters above sea level there are hardly any house dust mites or none at all. The same applies to deserts and Antarctica.
If the house dust mite allergy is not very pronounced, these measures are often sufficient to permanently reduce the symptoms.
Nevertheless, it is advisable to have the contact details of a doctor or an allergy ambulance ready in case of an emergency. If the house dust allergy symptoms are particularly severe (especially in combination with acute shortness of breath), rapid medical help is required.
Medicines for house dust allergies
Various medications are available for the acute treatment of house dust allergy symptoms. They are mainly used for more severe complaints.
Some of the remedies for house dust allergies are available in pharmacies without a prescription. However, it is advisable to consult a doctor before using any medication. Because every drug may have undesirable effects or show interactions with other drugs or foods.
In principle, the symptoms of allergic rhinitis (as occurs in the context of a house dust allergy) can be reduced with the following remedies:
- Antihistamines generally relieve allergy symptoms by inhibiting the release of histamine. They are used for allergic colds (e.g. caused by house dust allergies) as tablets or nasal sprays.
- Glucocorticoids (“cortisone”) as a nasal spray have a decongestant effect on the nasal mucous membranes. If necessary, they can also be used over a longer period of time – under medical supervision.
- Nose drops and nasal sprays with decongestants (alpha-sympathomimetics) help with nasal congestion. It is recommended to use this for a maximum of five to seven days. Otherwise, the mucous membrane will get used to it and the effect of the medication will decrease. Under certain circumstances, these preparations trigger nosebleeds.
- Leukotriene antagonists inhibit messenger substances that play an important role in inflammatory reactions in the airways. In addition to asthma symptoms, this may also alleviate the symptoms of allergic rhinitis. The doctor prescribes the medication if the patient suffers from asthma and allergic rhinitis at the same time.
- Mast cell stabilizers (cromones) prevent the release of histamine from the so-called mast cells (a type of immune cell). For allergic colds and allergic conjunctivitis, they are used as a nasal spray or in the form of eye drops.
Hyposensitization (specific immunotherapy) is used to try to treat the house dust allergy causally. Hyposensitization is particularly successful in children (from the age of six) and in the case of a house dust allergy that has only recently developed.
There are two possible approaches to desensitization:
- In subcutaneous immunotherapy (SCIT), the doctor injects the mite allergens under the skin in slowly increasing concentrations – initially usually once a week, later once a month. The body should slowly get used to the actually harmless mite proteins.
- In sublingual immunotherapy (SLIT) , the patient usually puts the mite allergens once a day as drops or tablets under the tongue, holds them there for one to two minutes and finally swallows them.
In both cases, the desensitization must be continued for at least two to three years until it shows its full effect. This then lasts for years. If the symptoms of the house dust allergy increase again, it is possible to repeat the hyposensitization.
House dust allergy: homeopathy and home remedies
Various homeopathic remedies are said to help with a house dust allergy, for example Sticta or Sabadilla. The effectiveness of homeopathy has not been scientifically proven. However, some patients report good results with homeopathic remedies. In addition, homeopathic treatment usually has no side effects.
The concept of homeopathy and its specific effectiveness are controversial in science and not clearly proven by studies.
In addition to homeopathic remedies, home remedies should also help against the symptoms of a house dust allergy. These include nasal rinses, which are carried out with a nasal douche, for example . However, a nasal douche usually does not replace drug treatment.
Home remedies have their limits. If the symptoms persist over a longer period of time, do not get better or even get worse, you should always consult a doctor.
Causes and risk factors
The actual cause of the house dust mite allergy is a dysregulation of the immune system :
No allergy symptoms appear on first contact with the allergen. The body nevertheless produces specific antibodies against the new and supposedly threatening foreign substance. Some of these antibodies are stored in the body.
Each further contact with the allergen then activates the specific antibodies and large amounts of histamine are released. This messenger activates the mechanisms that ultimately lead to the typical symptoms of house dust mite allergy.
Risk factors may favor the development of allergies. These include environmental factors such as cigarette smoke and air pollution.
House dust allergy: prevention and tips
So far, no specific measures that have been proven to prevent house dust mite allergy are known.
For example, a mite-proof mattress cover (encasing) is not recommended to prevent the development of a dust allergy (primary prevention). On the other hand, it is suitable for secondary prevention, i.e. for preventing allergic symptoms in the case of an existing house dust mite allergy.
There are general tips for those who want to reduce the risk of house dust allergies and other allergies. This is particularly advisable if allergies (of any kind) occur frequently in a family – the related family members probably have a hereditary predisposition to allergies (atopy).
For such atopics, it is particularly important to reduce contact with common allergy triggers such as house dust mites as much as possible.
This is done, for example, by reducing the number of mites in your own four walls . The tips are similar to those for people with an existing dust mite allergy (see Treatment section).
It is not known whether air purifiers with mite-proof air filters help with house dust allergies.
Breastfeeding reduces the risk of allergies in babies . Experts therefore recommend feeding babies exclusively breast milk for the first four months of their lives.
Subsequent diet also influences the allergy risk: There is evidence that a diet with lots of vegetables and fruit (Mediterranean diet) may prevent atopic diseases such as house dust mite allergy.
Course and prognosis
If it is possible to consistently reduce the allergen load, the symptoms of a house dust allergy can be significantly reduced or (in mild cases) avoided entirely.
Medications can also help relieve symptoms. A house dust allergy can be treated causally by hyposensitization. Good results are usually achieved with this: Those affected then need much less allergy medication or even none at all.
In the case of a house dust allergy, there may be a change of level over time: the allergy shifts from the upper to the lower respiratory tract – those affected develop allergic asthma.
How is house dust allergy diagnosed?
If a house dust allergy is suspected, a specialist in allergies (allergist) is the right person to contact.
In the first conversation with the patient, the doctor collects the medical history (anamnesis): He asks, for example, about the type and extent of the symptoms, personal circumstances and any other illnesses.
Because allergic reactions such as watery eyes and a runny nose have many possible causes, diagnosing a house dust allergy is often difficult.
The doctor therefore often asks the patient to keep an allergy diary for a while. There he enters when and to what extent the various complaints occur, whether they are only noticeable in his own home or also in other people’s households and what he was doing or eating before the complaints appeared.
This information may then reinforce the suspicion of a house dust allergy or indicate other possible allergy triggers (such as pets or food).
In the next step, if a house dust allergy is suspected, a corresponding test is carried out. This is usually the so-called prick test: With this examination method, the doctor drips various allergens onto the skin on the forearm or back. Then he slightly scratches the skin in the affected areas.
If the patient is not hypersensitive to an allergen, the skin will not show any changes. With an existing allergy, however, the skin under the allergen in question turns red or forms a wheal (red, usually itchy, small skin swelling) within about 20 minutes.
The skin’s readiness to react may be influenced by various factors such as acute infections or the use of certain medications. With the prick test, a specific allergy such as house dust allergy can neither be clearly proven nor ruled out.
Another examination method for suspected house dust allergies (or other allergies) are various blood tests.
Some tests only allow a statement to be made as to whether an allergy is present in general or not. Others, on the other hand, are more specific, such as the RAST test: This tests the blood for specific antibodies against certain allergens such as house dust mites.
If a dust allergy cannot be clearly identified using the tests mentioned, the doctor may carry out a provocation test. He applies the suspected allergen (in this case mite proteins) directly to the patient’s nasal mucosa.
If an allergic reaction occurs as a result, there is a high probability of a house dust allergy.
It is important that such a provocation test is always supervised by a doctor. If a severe allergic reaction occurs due to the house dust allergy, he will provide immediate help by quickly initiating appropriate countermeasures.