I get ferocious fits of allergic sneezing too - pollen or scented cleaning materials mostly. (Synthetic scents in cleaning sprays can set me off at levels so low I can't actually smell them; some trees are so allergenic at some times of year I avoid bus routes that go past them).

Antihistamines (loratadine, acrivastine, cetirizine) help, but what makes the largest difference is avoiding certain grain products, particularly bread and pastry wheat and dry-cooked oat biscuits. The concept is called "total allergic load" - if you're slightly allergic to one thing, exposure to it may produce a reaction to something else entirely. In my case it seems to be particles of dry foods like bread that cause trouble when they float up my nose.