Study designs of evaluations included in the review
Double-blind placebo-controlled trials were eligible for inclusion in the review.
Specific interventions included in the review
Trials investigating subcutaneous specific immunotherapy with house-dust mite extracts (Der p or Der f) were eligible for inclusion. Studies on sublingual, oral, intranasal and inhalation immunotherapy were excluded, as were those on therapies with antigen-antibody-complex or house-dust extracts. The patients had to have undergone a skin prick test regarding Der p or Der f. Studies were restricted to mono-sensitisation against Der p and/or Der f; those of sensitisation on several perennial allergens were excluded. In the included studies therapy lasted between 7 weeks and 2 years. Patients in some of the included studies also received a systemic steroid.
Participants included in the review
Adult patients with persistent perennial rhinitis or asthma bronchial and clinical symptoms, a positive skin prick test for Der p and/or Der f, and evidence for specific immunoglobulin E against Der p or Der f, were eligible for inclusion. Symptoms severity varied greatly in the included studies. The age of the participants varied between 5 to 50 and 13 to 68 years.
Outcomes assessed in the review
The studies had to report on subjective symptoms (using a visual analogue scale or a diary method), use of medication, lung function, or bronchial, nasal or conjunctival provocative test. Most of the included studies reported on bronchial provocative test reactions.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.