Autosomal Dominant Compelling Helioophthalmic Outburst (ACHOO) Syndrome is a genetic dominant disorder that results in uncontrollable sneezing in response to numerous stimuli, such as looking at bright lights, cold air, or strong flavors. The condition affects 18-35% of the population, and its exact mechanism of action is not well understood.
Photic sneeze reflex is an dominant hereditary trait which causes sneezing, possibly many times consecutively when suddenly exposed to bright light. The first mention of the phenomenon is probably in the later work attributed to Aristotle (c. 200 BCE).
The probable cause is a congenital malfunction in nerve signals in the fifth cranial nerve, called the trigeminal nerve, which is apparently responsible for sneezes. Research suggests that some people have an association between this nerve and the nerve that transmits visual impulses to the brain. Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex.
This sneeze reflex can also be brought on by sudden inhalation of cold air or exposure to strong flavors. This implies an overstimulation of any nerve close to the trigeminal nerve can cause the sneeze reflex.
Stomach fullness is another example of a stimulus that causes uncontrollable sneezing that may be linked to ACHOO syndrome. People who exhibit this symptom undergo uncontrollable fits of 3-15 sneezes immediately after eating large meals which completely fill the stomach. The so-called snatiation reflex occurs independently of the choice of food eaten, and is not believed to be an allergic reaction of any kind.
There is much debate about the true cause and mechanism of the sneezing fits brought about by ACHOO syndrome. Sneezing occurs in response to irritation in the nasal cavity. The most obvious difference between a normal sneeze and an ACHOO syndrome related sneeze is the stimulus – normal sneezes occur due to irritation in the nasal cavity, while ACHOO sneezes can result from a wide variety of stimuli.
A fit of sneezing while operating a vehicle can cause the operator to lose control of the vehicle, resulting in damage to the person, vehicle, and surroundings. In particular, photic sneezing poses a considerable risk to aircraft pilots, due to the presence of the bright sun and the precise reactions needed to successfully pilot an aircraft.
Uncontrollable fits of sneezing are common in patients under propofol sedation who undergo periocular injection. A sneeze by a sedated patient often occurs upon insertion of a needle into or around their eye. The violent and uncontrollable movement of the head during a reflexive sneeze has potential to cause damage within the patient’s eye if the needle is not removed before the sneeze occurs.
There is currently no definitive way to cure the sneezing fits brought on by ACHOO syndrome. Photic sneezing can be combated by shielding ones eyes with hats or sunglasses. There are many remedial fixes for sneezing, such as placing a finger horizontally below the nose or holding the nose closed when the beginnings of a sneeze are felt.
The Daily Omnivore 
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