ACHOO Syndrome
Definition
ACHOO syndrome is a generally benign condition characterized by sudden, uncontrollable sneezing after viewing a bright light.
Description
The ACHOO syndrome, standing for autosomal dominant compelling heliopthalmic outburst syndrome, is an inherited condition where a person will involuntarily sneeze after seeing a bright light. A person with this condition will sneeze multiple times, and in rare cases may sneeze 30-40 times. The syndrome is usually more intense if the person with the condition moves suddenly from darkness into an area with bright lights or sunlight.
Genetic profile
The ACHOO syndrome is thought to be inherited in an autosomal dominant pattern. This means that only
one copy of the abnormal gene needs to be present for the syndrome to occur. If one parent has the condition, their children will have a 50% chance of also having the syndrome. One physician reported the condition in a family, where it was observed in the father and his brother, but not seen in the father's mother or his wife. Both the father and brother would sneeze twice when going from an area of darkness to an area of light. At four weeks of age, the father's daughter also started to sneeze whenever she was moved into bright sunlight.
Because of the relatively benign nature of the condition, there has been no reported scientific work trying to locate the gene responsible for the syndrome.
Demographics
Occurrence of the ACHOO syndrome is widespread in the general population. The few well-documented studies performed report the condition as being present in 23-33% of individuals. Men seem to be affected more than women. Studies on the occurrence of the syndrome in various ethnic groups are very limited. One study showed differences between whites and non-whites, while another study showed no difference.
Signs and symptoms
The prominent symptom of people with the ACHOO syndrome is sudden, involuntary sneezing when they see a bright light or sunlight. The way in which sneezing is triggered is not very well understood, but there are several theories that attempt to explain the syndrome.
One theory is that people who have the ACHOO syndrome have a hypersensitive reaction to light, just like some people have a sensitivity to cat hairs or pollen. When a person with the syndrome is exposed to a bright light, the same mechanism in the body that triggers a sneeze due to an irritant such as pollen somehow confuses light with that irritant and causes a sneeze to occur. Another idea is that the sneeze reflex in people with the ACHOO syndrome is somehow linked to real nasal allergies, although this does not explain the syndrome in people without nasal allergies. A third theory is that people with the ACHOO syndrome are very sensitive to seeing bright light. The sneeze reflex of the syndrome can then be thought of as an involuntary defense reaction against bright light; when the person sneezes, they automatically close their eyes.
