Sneezing is a normal reflex that occurs in response to irritation in the nasal passages. In most cases it is acute, lasting anywhere between a few minutes to several days often caused by airborne irritants like smoke or acute upper respiratory tract infection like the common cold. If it persists and occurs frequently, either as bouts of sneezing fits or intermittent sneezes that occur constantly throughout the day, then it may be related to a chronic condition even though other signs and symptoms are absent.
Most cases of chronic sneezing are related to allergies. The immune-mediated hypersensitivity may be triggered, but not caused, by inhaled or even food allergens. Exposure to smoke and other inhaled irritants like dust may trigger sneezing even in a person without allergies but in an allergic individual, these irritants aggravate an existing condition.
Other signs and symptoms that may be present along with a persistent sneeze includes :
- Runny nose (rhinitis)
- Itchy nose
- Nasal congestion
- Diminished or loss of smell (hyposmia, anosmia)
- Redness of the nares (nostrils)
- Watery eyes (excessive lacrimation)
- Red eyes, blood shot eyes
- Itchy eyes
- Itchy nose
Causes of Chronic Sneezing
Most causes of chronic sneezing is often associated with rhinitis (runny nose). These causes are also discussed under Runny Nose and Sneezing.
As mentioned above, allergies account for the most common cause of chronic sneezing. This is often seen in allergic rhinitis, which may either be perennial (present all year) or seasonal (occurs intermittently, usually during certain seasons like spring). While airborne allergens are a more aggressive trigger, it is not uncommon for atopic individuals to also experience reactions to food allergens like dairy.
A characteristic feature of allergic rhinitis is the morning sneezing fit. Here an individual erupts in bouts of repeated sneezing upon awaking from sleep. Other symptoms like nasal congestion, runny nose (rhinitis), watery eyes and itchy eyes especially in the late evening may also be present.
Seasonal rhinitis is characterized by sudden, frequent attacks of sneezing. Hay fever which is the most common type of seasonal allergic rhinitis is often triggered by pollen (grass, tree or flowers).
Perennial rhinitis occurs in response to more specific antigens like pet hair (dander), house dust mite and fungal spores. Patients may also complain of sneezing when exposed to perfumes and other strong odors, changes in weather and cold, dry air (like air conditioning).
Sensitivity to food allergens are more frequently seen in children with a history of atopic conditions like eczema, allergic rhinitis and asthma. Adults, however, may also respond to foods and drinks, although this is often related to temperature like with icy cold drinks or hot and spicy foods (gustatory non-allergic rhinitis explained below).
Most upper respiratory tract infections are acute in nature. Sneezing is often one of the first symptoms and is short-lived. However with chronic infections, which may be seen in immunocompromised patients, sneezing may be persistent.
The most common causes of infectious rhinitis are viral infections, particularly adenoviruses and rhinoviruses. Bacterial infections are also responsible for rhinitis but in cases of chronic symptoms, it may more often be linked to sinusitis. Fungal infections are rare but could also lead to chronic sneezing and rhinitis – it is more likely to be seen in patients with impaired immune functioning like mucormycosis in diabetics.
Airborne, systemic and ingested irritants may cause persistent sneezing if there is constant exposure to it. Some of the triggers include :
- Environmental pollution (like smog)
- Organic and inorganic dusts
- Cigarette smoking (secondary smoke inhalation)
- Strong odors from perfumes and spices
- Spicy foods
- Dry weather
- Hormonal changes – pregnancy or contraceptives
This is commonly seen in non-allergic rhinitis which has different sub-classifications including :
- Infectious rhinitis
- Vasomotor rhinitis
- Gustatory rhinitis
- Hormonal rhinitis
- Occupational rhinitis
- Drug-induced rhinitis
- Non-allergic rhinitis with eosinophilia syndrome (NARES)
For more information, refer to Types of Rhinitis.
Chronic sneezing related to the use of certain medication is encompassed under drug-induced rhinitis. However medication that leads to excessive drying of the nasal passages may also be responsible and in these cases there is no signs of rhinitis. Some of the medication involved may include :
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Hypertension medication like beta-blockers
- Nasal decongestants (overuse leads to rebound rhinitis)
- Oral contraceptives
- Drugs for erectile dysfunction
- Neurological conditions that may affect the trigeminal nerve or sneeze center in the medulla
- Nasal polyps
- Cocaine sniffing
- Tobacco sniffing (snuff)
- Professional swimmers (chlorinated pool water)