What could cause excessive sneezing?

There are several factors that could cause sneezing. Any foreign particle that can get past the nasal hairs can stimulate the sneeze reflex. These can include seasonal allergies like those caused by pollen, or dust and pet dander. Strong odors from perfumes, tobacco smoke or cooking can also stimulate sneezing. Viruses, cold or hot weather and drying of the nasal lining are also culprits in excessive sneezing. In rare instances, bright sunlight can also trigger the sneeze reflex.