House dust mite allergy is very common and may be the most common cause of year-round allergy and asthma.
Key points
- Many people with asthma, eczema and hay fever (allergic rhinitis) are allergic to a protein found in the microscopic waste of dust mites.
- It may be the most common cause of year-round allergy and asthma.
- Dust mite allergy can be diagnosed with a skin prick test which helps to find out what triggers your allergy.
- There are a few, easy steps that can be taken to reduce house dust mite population and keep it minimal, such as hot washing bedding on a weekly basis and keeping your home well-ventilated and dry. Antihistamines can also help manage the condition.
- If dust mite allergy continues to be a problem despite these measures, consider desensitisation therapy.
What are dust mites?
House dust mites are tiny bugs, too small to see without a microscope, which are present wherever people live. They thrive in warm, moist places such as mattresses, bedding and carpets, and feed mainly on flakes of dead skin, which humans constantly shed.
- Dust mites don't bite or pass on disease. They are only a problem to people who are allergic to their waste.
- A female dust mite can lay up to 300 eggs during its short 80-day lifespan and, during its lifespan, a single dust mite can produce as much as 200 times its body weight in waste.
- Within the waste is a protein that is an allergen – a substance that starts an allergic reaction in many people.
What are the symptoms of dust mite allergy?
If you have an allergy to dust mites, you will have hay fever-like symptoms all year round, such as runny nose, sneezing, sinus congestion. Signs that you might have an allergy to dust mites include:
- wheezing when you are vacuuming, dusting or spring cleaning
- allergy symptoms like runny or blocked nose or itchy eyes all year
- wheeze or cough when you enter a dusty room or house
- asthma symptoms during the night or first thing in the morning.
Complications of dust mite allergy
Sinus infections
Ongoing inflammation of tissues in the nose caused by dust mite allergy can block your sinuses, the hollow cavities connected to your nasal passages. These blockages may make you more likely to develop infections of the sinuses.
Asthma
People with dust mite allergy and asthma often have difficulty managing asthma symptoms. Managing the dust mite allergy will often reduce the frequency and severity of asthma symptoms.
How is an allergy to dust mite diagnosed?
If you think you may be allergic to dust, or dust mite, ask your doctor for a skin prick test to help find out what is triggering your allergy. The skin prick test is done by applying drops of different allergens (such as dust mite extract) onto the forearm skin.
- These are numbered so the tester knows which is which.
- Then a tiny prick is made within each drop of extract.
- You then need to wait for 15 minutes – if you are allergic an itchy red bump (like an insect bite) will appear at the site.
What can you do about house dust mites?
The best treatment for dust mite allergy is to avoid contact with the mite. Total avoidance of dust mite is impossible, but here are a few tips on how to reduce house dust mite population:
Environment |
Suggestions |
Ventilation |
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Bedroom/bedding |
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Carpets |
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Soft toys |
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General |
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Medications for dust mite allergy
If you are unable to avoid dust mite waste (which is difficult to do in New Zealand homes where dust mites thrive), you may need to talk to your doctor about medications to help control the allergic reactions. These are called antihistamines and come in different forms, including tablets, nasal sprays, eye drops and syrups.
Desensitisation therapy
If other methods of managing dust mite allergy are not effective, desensitisation therapy may be considered. This treatment is also called immunotherapy or allergen vaccination and is done by a clinical immunologist. It involves a series of injections of the allergen just below the skin surface. The injections start off with a very small amount of the allergen and the dose is gradually increased so that your body builds up immunity to the allergen. After the maximum dose is given, regular injections are given for 3 to 5 years to keep up the immunity.
Learn more
Dust mite allergy Allergy NZ
House dust mite DermNet NZ
Allergen minimisation Australasian Society of Clinical Immunology and Allergy
Treatment for dust mite allergy Mayo Clinic USA
References
1. Disease Summaries: Allergic Asthma: Symptoms and Treatment World Allergy Organisation