How long does a dust mite allergic reaction last?

It depends... On the amount and duration of exposure. If you're allergic to dust mites and you fluff up a pillow on the way to the washing machine, probably 30 minutes. If you sleep on a pillow without an allergy cover, the all-night-long exposure might last a couple of hours, or if you're highly allergic to dust mites, it might last all day.
Chronic on-going. Dust mites are very prevalent indoor allergens causing rather constant exposure for many people. The allergic reaction to a single acute exposure to an allergen may last up to 48 hours, however, people generally have a more constant exposure to dust mites and reactions become on-going.

Related Questions

Can stress (or anything other than the allergen) be a factor in the frequency or severity of a dust mite allergic reaction?

You bet. Sress can be a factor in each and every disease idirectoly, sress ( ulcers, headache, adrenal outpore, obesity and so on) under stress you donot clean the house and then balme the allergens. So find out the cause of sress and work on, get rid od carpet in the bedroom, where you inhale dustmite for 8 hrs costantly. Read more...
Stress worsens. Our bodies are so complex, and we really only understand a fraction of how our bodies' systems interact with our environment. In general, chronic ongoing stress seems to worsen many illness. So yes, i'm sure stress has the potential to worsen allergy. It's good to make a concerted effort to lessen overall stress. See stress reduction techniques on health tap. Read more...