It has long been understood that warm moist environments create a breeding ground for the proliferation of bacteria and yeast. Theoretically then the warmer, heated facial skin of a rosacea flare would also create a breeding ground for the proliferation of bacteria and germs. This would give some credence to the theories that mites are a factor in rosacea.
Mites and bacteria may not cause rosacea but in fact the rosacea may in fact be the stimulus that triggers increased mites production and bacteria growth. Studies at various universities on the possible correlation between dust mites and or a bacterial component of rosacea have found that: 1) the skin of rosacea patients in a rosacea flare does tend to be warmer that a person not experiencing a rosacea flare; 2) warmer skin temperatures result in the increased production of lipase protein enzymes that can break down the sebaceous oil barrier of the skin.
Rosacea is very much a condition of cause and effect. The triggers for rosacea cause an increased response to rosacea symptoms. But in the case of dust mites and bacteria, rosacea is the trigger that results in an increased response of growth among bacteria and dust mites.