Dear Dr. Toshi,
I get uncontrollable morning sneezing. Can you talk about that?
It's impossible for me to diagnose a specific condition without seeing and examining the person, but we can talk in general about sneezing and possible causes of "morning sneezing."
Sneezing can be annoying, as we all know. Sneezing is an upper airway reflex. Upper airway means the upper respiratory tract which includes the nose, the nasal passages deeper inside the nose, the sinuses (internal cavities around the nose/face), the pharynx (throat) and the portion of the larynx (lower portion of the throat) above the vocal cords. When the upper airway is stimulated, the nervous system gets engaged, resulting in reflexes like sneezing. Other things that stimulate the upper airway to elicit the sneeze reflex include nasal itchiness, a runny nose, and nasal congestion (stuffy nose). Many things can stimulate the nervous system to cause sneezing, such as mechanical probing (like nose picking!), saline washes, cold or dry air, histamines, allergens (things that cause allergies, like pollens), nicotine, and capsaicin (the substance that makes food spicy hot). There are also other stimuli for certain people, including bright light, a full stomach, and injections around the eyes (e.g., anesthetic shots that are given during cataract surgery).
Sneezing is controlled in the brainstem part of the brain, and certain nerves in the face are known to directly stimulate sneezing as well. There are many chemicals in our body that play roles in this mechanism, and scientists are continuing to research this. You may have noticed that if your nose is irritated, you tend to sneeze. You might have an allergy to dust, for example, so you start sneezing because your nasal passage is irritated and stimulated.
Some people (as many as one out of every three people) have an inherited condition called the "photic sneeze reflex." It's also known as the "light sneeze reflex" or "solar sneeze reflex." When that person is suddenly exposed to bright light like sunlight, or has a full stomach, or gets an injection around the eye for eye surgery, for instance, he or she could start sneezing uncontrollably. This isn't an allergic reaction, it's an activation of nerves (neurons) which stimulate sneezing by other neurons, specifically neurons involving the eyes. That is, neurons coming from the eyes happen to run right next to other neurons that stimulate sneezing.
So, if someone often has sneezing in the morning, it could be due to sudden exposure to morning sunlight. (Or it could just be due to dust or nasal drainage, too.) It's known that uncontrollable sneezing often occurs when people with this condition come out into the light after spending time in a dark environment. So, if you sleep in a dark room and come out into the bright morning sun, that could trigger uncontrollable sneezing.
Uncontrollable sneezing is mostly just annoying and not really harmful to the health, so not much research is done in this area. However, sneezing during certain activities like driving or operating huge farming equipment can be very dangerous. Several years ago, I heard about an elderly lady who got into a major car accident because she started sneezing and lost control of her car. Sneezing can also be very dangerous to other people because it can spread diseases quickly by spraying microscopic organisms such as viruses and bacteria out in microdroplets that float in the air for other people to inhale.
Some studies have shown that sneezing caused by the light sneeze reflex may be improved with over-the-counter allergy medication (an antihistamine) even though it's not an allergic reaction. It's also recommended that people who are affected by this avoid sudden exposure to bright light by doing things like wearing sunglasses, keeping their window shades down, and so forth.
Dr. Toshiko ("Toshi") Luckow, MD, is a Family Physician at the West River Health Services Hospital and Clinics.