One in 20 children and one in five adults will test positive for HDM allergy, although not all will have symptoms. One in three children with eczema and asthma will test positive to HDM.
HDM allergy commonly causes all year-round symptoms. These include sneezing, runny nose, coughing, or itchy red, watery eyes. HDM can also trigger asthma and eczema. It is not usually associated with life-threatening allergies.
HDM allergy is caused by tiny creatures that are distantly related to spiders! They thrive in warm damp conditions and feed on shed skin. They are found in homes no matter how clean. Allergy is caused by small participles of HDM faeces, the size of pollen grains. It is therefore not surprising that mite allergy and pollen allergy cause similar symptoms.
Four out of five patients with HDM allergy are also allergic to pollen or animal dander.
Skin prick tests or a blood test can show if you have allergy antibodies to house dust mites.
It is not possible to completely remove HDM from your home. Focus your efforts on the bedroom and living room where you or your child spend the most time. Avoid damp and dusty places.
Your bed (mattress and pillowcase) is the perfect breeding ground. HDM can also be found in large numbers in soft furnishings, carpets, curtains, clothes and fluffy toys.
The following can reduce the amount of HDM in your home:
- Dust surfaces weekly with a damp cloth and vacuum weekly using a vacuum cleaner that has a high-efficiency particulate air (HEPA) filter. The person with HDM allergy should not be in the room when cleaning is done, as high levels of dust in the air occur during cleaning.
- Air the room by opening the windows.
- Do not sleep on the lower bunk bed.
- Remove clutter, soft toys, and carpets in the bedroom.
- Wash bedding and covers regularly at 60°C to kill dust mite.
- Put soft toys that cannot be washed at 60°C in the freezer first (for 12 hours).
Firstly, reduce exposure to HDM by taking measures that are simplest and cheapest.
Secondly, use either a non-sedating antihistamine (such as cetirizine or loratadine), or a nasal steroid spray. Some patients get more benefit from taking both together. These may need to be used regularly for a long time.
If nasal symptoms persist, your doctor may recommend additional treatment with montelukast, particularly if you have asthma.
Antihistamines and nasal steroids do not cure the allergy. They just treat the symptoms.
If despite taking your treatment regularly you still have troublesome symptoms, desensitisation (immunotherapy) may be offered by specialist children’s allergy centres. Immunotherapy can reduce symptoms but does not completely cure the allergy. The programme of treatment is three years long and may not be suitable for all patients.
Most children with HDM allergy will not outgrow the problem. However, the allergy can be helped by lifestyle changes and use of medication.