<P> A condition called gustatory rhinitis can cause some individuals to sneeze after eating, particularly after the consumption of spicy foods . Stomach fullness is another example of a stimulus that can cause uncontrollable sneezing . Those who exhibit this symptom or disorder, called snatiation, undergo uncontrollable fits of 3--15 sneezes immediately after eating large meals that completely fill the stomach, regardless of the type of food eaten . Snatiation is not believed to be an allergic reaction of any kind . Even less well understood than photic sneezing and sneezing in response to periocular injection, the trait appears to be inherited in an autosomal dominant fashion . </P> <P> Another related condition is sonar sneezing, in which exposure to loud noises or loud environments triggers a sneeze response . </P> <P> There is much debate about the true cause and mechanism of the sneezing fits brought about by the photic sneeze reflex . Sneezing occurs in response to irritation in the nasal cavity, which results in an afferent signal propagating through the ophthalmic and maxillary branches of the trigeminal nerve to the trigeminal nerve nuclei in the brainstem . The signal is interpreted in the trigeminal nerve nuclei, and an efferent signal goes to different parts of the body, such as mucous glands and the diaphragm, thus producing a sneeze . The most obvious difference between a normal sneeze and one caused by the photic sneeze reflex is the stimulus--normal sneezes occur due to irritation in the nasal cavity, while the latter can result from a wide variety of stimuli . Some of the theories regarding the mechanism of a sneeze resulting from an unusual stimulus are below . There is also a genetic factor that increases the probability of photic sneeze reflex (19). The C allele on the rs10427255 SNP is particularly implicated in this (19), although the mechanism by which this gene increases the probability of this response is unknown . </P> <P> Stimulation of the ophthalmic branch of the trigeminal nerve may enhance the irritability of the maxillary branch, resulting in an increased probability of sneezing . This is similar to the mechanism by which photophobia develops by persistent light exposure relaying signals through the optic nerve and trigeminal nerve to produce increased sensitivity in the ophthalmic branch . If this increased sensitivity occurred in the maxillary branch instead of the ophthalmic branch, a sneeze could result instead of photophobia . </P>

Why do i sneeze if i look at the sun