I'm sure eucalyptus leaves will help, also if you use 10-20 drops of the essential oil with water in a spray bottle and you spray that onto the mattress that will help as well.
Speaking of allergies, the one oil that I've come across that has the potential to exacerbate your allergies is Chamomile.
Thanks so much for the reply. I'll try the leaves. The oil spray sounds positive, though it seems it might gunk up the mattress after a while. Then again, gunk might be better than those pesky, all-prolific dustmites. (You don't really want to think very hard on how many ounces of them are living you your bed). ( :
And thanks for the tip on chamomile. Allergies are so unpredictable.