How to avoid dust allergies when away from home?

Not easy, use meds. Allergy symptoms are expected when exposed to what cause them in a particular person. Know where you will stay in advance, if there is a choice, prefer non-carpeted, vacuumed rooms. Remember to use maintenance medications to prevent allergy flare up. Use nasal/sinus saline washes to reduce dust in nose passages. Stay outdoors if there is no pollen allergy.
Agree with Dr Chinen. I agree with dr. Chinen. I also suggest that my patients purchase 2 or 3 pillow encasements for house dust mite. Keep one in their suitcase. They cost about $10 each. Use it on the trip & hopefully remember to take it when coming home. True all the bedding will not be encased but your pillow is where you put your eyes and your nose at night. Worst case scenario you're out 10 bucks.