what causes a runny nose and sneezing?
<answer> Allergens, viruses like the common cold or flu, nasal irritants, inhalation of corticosteroids through a nasal spray, or drug withdrawal, the release of histamine from allergic cells in the nasal mucous membranes, known as allergic rhinitis. <context> When these membranes become irritated, it causes you to sneeze. Sneezing can be triggered by allergens, viruses like the common cold or flu, nasal irritants, inhalation of corticosteroids through a nasal spray, or drug withdrawal.