House dust mites are ubiquitous in homes and workplaces – with health consequences for many allergy sufferers.
The house dust mite is an arachnid about 0.3 mm in size and not visible to the naked eye. There are around 150 species of house dust mites in the world. One mite produces up to 40 faecal droppings a day. One teaspoonful of bedroom dust contains an average of nearly 1000 mites and 250,000 minute droppings.
Causes and triggers of house dust mite allergy
Symptoms of house dust mite allergy
Diagnosis and differential diagnosis
Therapy and treatment
Tips and tricks
Facts and figures
The house dust mite requires a warm, moist environment without light in order to live and reproduce. Our beds are ideal. The mite feeds on human and animal skin scales. The allergen is mainly contained in the mite’s faeces. The faeces contain allergy-triggering constituents which are spread in fine dust, are breathed in and can cause an allergic reaction.
When the allergens come into contact with the mucous membranes in the eyes, nose, mouth and throat, sufferers develop symptoms typical of an allergic cold (allergic rhinitis) or an allergic inflammation of the conjunctiva (allergic conjunctivitis): blocked or runny nose, sneezing, red, itchy eyes. If all of these symptoms are present, then the condition is also known as rhinoconjunctivitis. Often, the upper respiratory tract becomes chronically inflamed, primarily because house dust mites are present all year round.
The symptoms of house dust mite allergy typically occur in the morning and are more frequent in the cold months of the year.
The diagnosis is based on thorough history-taking with the aid of skin and blood tests. Similar symptoms can occur in cases of pollen or mould allergy. Differences can mainly be identified in the place and time of onset of the symptoms. This is why it is worth observing the symptoms accurately.
As a first step, mattress, pillows and duvet should be placed in mite-proof or anti-mite covers, sometimes known as encasings. At the same time, house dust should be minimised. If necessary, the symptoms can be treated with medication, for example antihistamines in the form of nasal sprays, eye drops and tablets. Desensitisation/specific immunotherapy (SIT) is recommended for house dust allergy.
Holidays at altitudes above approximately 1200 metres above sea level are advisable. However, mites can survive for up to 6 weeks in hotel beds (every guest introduces mites). A dry climate is basically hostile to mites. In Switzerland 6.5 % of children and adults are affected by allergy to house dust mite.