How to treat this really depends on what is causing it. Unfortunately, there are many possible causes of this problem. Fortunately, there are a few clues that your doctor
can use to diagnose and subsequently treat it. Therefore, I would recommend that you see your primary care doctor
There are a few causes of sneezing. Keep in mind that sneezing is a process by which the body attempts to clear debris from the nasopharynx (the nasal passages). One major cause is infection. Infection of the sinuses can cause chronic sneezing and is known as chronic sinusitis. Various antibiotics, steroids or even surgery
may be needed, however your doctor will first need to evaluate you before making this diagnosis.
Probably the most common cause of chronic sneezing is not infection but actually allergies. Allergies can cause inflammation in the nasal passages and result in sneezing. Allergies can be developed to really anything in the environment and therefore can cause ubiquitous sneezing. Luckily, there are many good treatments for this, including over the counter anti-histamines. I would recommend discussing this with your doctor prior to starting any medicine.
There are other rare causes. I would recommend talking to your primary care doctor to have this evaluated. Good luck!