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Sneezing

Causes of Sneezing

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Updated December 28, 2009

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Sneezing is one of the most recognizable allergy symptoms – many advertisements for allergy medications include pictures of people standing outside sneezing. But what actually causes sneezing? Are there other things that cause sneezing besides allergies? What are the best treatments for sneezing? Let's look at the many causes and possible treatments:

Allergic Rhinitis

When you are allergic to something, you may sneeze. This is caused by the release of histamine from allergic cells in the nasal mucous membranes, known as allergic rhinitis. Histamine acts on various nerves within the nasal mucous membranes, which causes a person to sneeze (and it also causes other typical allergy-related problems, like a runny nose). Sneezing may help prevent the inhalation of dangerous substances into the lungs, including allergens. Antihistamines, in both oral and nasal forms, are often good treatment choices for sneezing caused by allergic rhinitis.

Infections

Respiratory tract infections, such as the common cold, can also cause sneezing. Colds cause mucous production, which in turn stimulates various nerves within the nasal mucous membranes. Sneezing is an example of a symptom that makes to difficult to tell the difference between symptoms of a cold compared to allergies. In the case of a cold, however, histamine is not causing the sneezing, so most antihistamines would not be expected to help the symptom. However, medications that can dry nasal secretions, including some antihistamines such as Benadryl, as well as anticholinergic nasal sprays such as Nasal Atrovent, can help with sneezing.

Irritants and Other Triggers

Remember those old cartoons when black pepper was used to cause a character to go into a sneezing attack? Black pepper acts as a chemical irritant on the nerves in the nasal mucosa, which causes sneezing. Other chemical irritants that can cause sneezing include strong odors, perfumes, and tobacco smoke; these triggers cause non-allergic rhinitis, since there are no allergic antibodies causing the symptoms.

Physical irritants such as bright sunlight can also cause sneezing, which is called the naso-ocular reflex. This involves a reflex connection between the eyes and nose, which causes stimulation of nerves within the nasal mucous membranes, resulting in sneezing.

For treating this problem, chemical and physical irritants do not cause sneezing through the release of histamine, so traditional antihistamines would not be expected to treat symptoms caused by these irritants. Instead, various nasal sprays, including nasal steroids, some nasal antihistamines, and anticholinergic nasal sprays, may be helpful for treating sneezing caused by chemical and physical irritants.

Sources:

Diagnosis and Management of Rhinitis: Joint Task Force on Practice Parameters in Allergy, Asthma and Immunology. Ann Allergy Asthma Immunol. 1998;81:463-518. DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.

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