Ghazala 2004.

Methods	Randomised cross‐over study
Participants	30 subjects with mean age 29.8 years complaining of allergic rhinitis or asthma
Interventions	Using encasings that were impermeable to mite allergens
Outcomes	Allergen (Der p1, Der f1 and mite group 2) content Subjective clinical complaint
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	"The randomisation of the patients was conducted by an independent person"
Allocation concealment?	Low risk	Independent allocation
Blinding?	Low risk	"A double‐blind placebo‐controlled crossover study"
Incomplete outcome data addressed? All outcomes	High risk	"Of the 30 patients who fulfilled the entry criteria, 4 fell out due to non compliance (non attendance of appointments and not filling in of diary)". They appear not to have undertaken an intention‐to‐treat analysis.
Free of selective reporting?	Low risk	All of the study's pre‐specified outcomes are reported
Free of other bias?	Unclear risk	The primary outcome of quality of life was studied using quality of life measures that have been validated in English (although whether or not these had formally been validated in German is unclear)