These microscopic organisms, which are related to spiders, live in many homes. Too small to see with the naked eye, dust mites thrive in warm, humid environments - eating dead skin cells and nesting in dust-collecting bedding, fabric, carpet and furnishings.
The residue that dust mites leave behind in the form of their feces and decaying bodies mixes with dust and becomes airborne. Inhaling the residue can cause allergy symptoms, including wheezing, sneezing, watery eyes and runny nose.
If you have a dust mite allergy, you may exhibit the signs and symptoms of hay fever (allergic rhinitis).
Dust mite allergy symptoms may include:
If you have asthma, you may also experience increased signs and symptoms of asthma, such as:
You may be especially prone to asthma attacks at night, when sleeping in a bed infested with dust mites. A dust mite allergy can range from mild to severe. A mild case of dust mite allergy may result in an occasional runny nose, watery eyes and sneezing. In severe cases, the condition is chronic - resulting in, for example, persistent wheezing, sneezing, congestion and facial pressure.
Allergens produced by house dust mites are among the most common triggers of asthma. Studies have shown the mean attributable fraction of adult asthma due to atopic sensitization was 30% and 18% for sensitization to dust mites. Taken into consideration this could mean as many as 1.2 billion people could have some form of chronic sensitization to dust mites.
The allergy occurs because the immune system of allergy affected individuals, for reasons not fully understood, misinterprets a usually innocuous substance as a disease agent and begins producing a type of antibody against it, called immunoglobulin E (IgE). This is called the 'primary antibody response.' The IgE produced during this response binds to basophils in the bloodstream and to a similar type of cell called mast cells in the tissues. When the person again encounters the allergen, these basophils and mast cells that have bound to IgE release histamine, prostaglandins and leukotrienes, which causes inflammation of the surrounding tissues, resulting in allergic symptoms. Most treatment has relied so far on trying to counteract the released chemicals with anti-histamines, Corticosteroids or Salbutamol. Commercial brands of these medications include Montelukast or Ventolin.
Newer methods to try to treat house dust mite allergy involve immunotherapy. A safety and tolerability clinical trial (Phase IIa) has been completed with positive results by Cytos Biotechnology using an immunotherapeutic (CYT003-QbG10) for treatment of house dust mite-triggered allergies. The French biopharmaceutical company Stallergenes is developing, via the Stalair Program, sublingual desensitization treatments for house dust mite allergy. The immunotherapy tablet, "Actair", has demonstrated efficacy after 4 months of treatment and the persistence of its therapeutic effect after only one year of treatment. (study VO57.07 conducted in Europe) Stallergenes is now preparing filing NDA in Germany. A phase III pediatric study has been launched.
Typical symptoms of house dust mite allergies are itchiness, sneezing, inflamed or infected eczema, watering/reddening eyes, sneezing repeatedly and frequently; e.g on waking up sneezing 10 or more times, runny nose and clogging in the lungs.
At present, the best form of treatment for dust mite allergies is avoidance of dust mites and their allergens combined with medication such as anti-histamines, Corticosteroids or Salbutamol. The environment of bedding is optimal for most dust mites, and comparative studies have shown that the density of dust mites in mattresses to be on average greater than 2500/gram of dust. Cleaning beds with most vacuum cleaners will not remove dust mite allergens, but instead throw them into the air and increase their volatility. Some polyethylene bedding is beneficial as it makes the environment difficult for the dust mites. This bedding should also be breathable and be able to withstand frequent washing.
A home allergen reduction plan has been recognized as being an essential part to the management of asthma symptoms and therefore all aspects of the home environment should be considered (proper vacuuming, use of air cleaners, etc.). The Asthma and Allergy Foundation of America as well as the Asthma Society of Canada certify products that may be used in a home allergen reduction plan in a Program called Asthma and Allergy Friendly.