Open questions — environmental-triggers (round 6)

• Does a single, easy house dust mite measure (e.g. impermeable mattress encasings alone) help toddlers who are proven mite-sensitised? Cochrane 2015 called for long-term trials; none in 1–4-year-olds found.
• For a toddler who already has eczema and a cat at home, does removing the cat improve eczema, and does the answer differ by filaggrin status? No RCT of pet removal was found.
• Do routine childhood vaccinations or intercurrent viral illnesses measurably trigger eczema flares in toddlers? Sources reviewed list infections as triggers but give no data on vaccines.