Every morning i get this cold and sneezing which lasts about an hour or two after which it disappears, what could it be..?

House dust allergy: One of the most likely causes of early morning sneezing is house dust mite or mold allergy. These common household allergens are in the mattress, pillows and rugs. They are virtually impossible to eradicate. Even a good humidifier can not lead to an absolute dust free home. The fact that it disappears in an hour is the result that you are probably out of the house within an hour or two.