My husband once a while has a very bad allergy and sneezes continuously which is a worry most times. we still do not know what the cause is. ?

Allergic rhinitis: This sounds like an acute allergic rhinitis reaction. Seasonal and intermittent symptoms are often dealt with successfully by using a triad of antihistamine, nasal steroid spray and saline nasal irrigation. Remember "the solution to pollution is dilution." If symptoms persist allergy testing may be indicated followed by immunotherapy (allergy shots) for refractory symptoms.