House dust mite allergy has serious affects on the sinuses. This can leave you feeling drowsy, congested and dizzy and taking endless medication. A hot bath or shower can have a great therapeutic effect and leave you feeling revived. The hot water has the effect of relaxing and expanding the sinuses, while the steam also has a thinning effect on the mucus and can allow you to breathe more easily. Try a long, luxurious bath next time you wake up a with a sore head from blocked sinuses, and feel your symptoms start to melt away.