Cochrane: Eczema
is an intensely itchy skin disease that tends to involve skin creases,
such as the folds of the elbows or knees. It is a worldwide problem
affecting 5% to 20% of children. Around 2% of adults have the condition,
and many have a more chronic
and severe form. As many as a third of people with eczema who have a
positive test for allergy to house dust mite have reported worsening of
eczema or respiratory symptoms when exposed to dust.
Ways to reduce or
avoid exposure to house dust mite, such as covers for mattresses and
bedding, increased or high-quality vacuuming of carpets and mattresses,
or sprays that kill the mites, could lessen the severity of eczema for
those who are sensitive to house dust mite. In this review, we aimed to assess the effects of all house dust mite reduction and avoidance measures for the treatment of eczema.
Review question
Do house dust reduction and avoidance measures provide a successful way to treat eczema?
Study characteristics
We found seven randomised controlled trials, which included 324
adults and children with eczema. We conducted the search up to 14 August
2014. Two of the seven trials included only children; four included
children and adults; and one only included adults. Four of the seven
trials compared treatments made up of multiple different house dust mite
reduction and avoidance measures, and three trials tested a single
treatment. The treatments were compared against other house dust mite
reduction or avoidance treatments, no treatment, a placebo intervention (e.g., cotton bed covers), or standard care only.
Key results
We did not find any evidence to inform clinical practice. Some small
treatment responses reported were in people with atopic eczema who were
sensitive to one or more airborne allergens. We found no evidence of
benefit in the other six included studies. Therefore, their use in the
eczema population
as a whole is unknown. High-quality longer trials of single,
easy-to-use house dust mite reduction or avoidance measures should be
performed.
Quality of the evidence
These seven very low-quality (Grading of Recommendations Assessment,
Development and Evaluation (GRADE) approach) small trials do not provide
enough evidence to recommend any of the house dust mite reduction and
avoidance measures tested.