Sneezing

Sneezing is a reflex expulsion of air through the nose and mouth triggered by nasal irritation. Persistent, paroxysmal or excessive sneezing most often indicates allergic or non-allergic rhinitis.

Mechanisms. Trigeminal sensory input to the brainstem sneeze centre from mucosal histamine, irritants, cold air, bright light (photic sneeze reflex), and strong smells.

Classification. Allergic rhinitis (seasonal, perennial, occupational), infectious rhinitis, non-allergic rhinitis (vasomotor, irritant, NARES, drug induced), physiological reflexes (photic, post-prandial, ethanol), and rarely neurological or psychogenic.

Key distinctions. Sneezing with itch of the nose, eyes and palate, and watery discharge points to allergy. Sneezing with fever, malaise and sore throat points to infection. Sneezing triggered by smells, temperature or humidity without itch points to non-allergic rhinitis.

History. Pattern (seasonal, perennial, occupational, nocturnal), triggers (pollen, dust mites, animals, moulds, smoke, perfumes, cold air, light), accompanying itch, discharge, obstruction, smell loss, eye symptoms, cough, wheeze, eczema, family atopy, home and work environment, pets, bedding, damp, and response to antihistamines.

Drug history. ACE inhibitors, beta blockers, alpha blockers, phosphodiesterase inhibitors, aspirin and NSAIDs, topical decongestants, and cocaine.

Examination. Nasal mucosa (pale, boggy, blue grey in allergy; red in infection), turbinates, discharge, polyps, septum, allergic salute and nasal crease, conjunctivae, throat (cobblestoning), ears (effusion), chest (wheeze), and skin (eczema).

Red flags

• Unilateral symptoms with blood stained discharge or obstruction
• Periorbital swelling or visual change
• Symptoms with wheeze, difficulty breathing or anaphylaxis
• Fever, facial pain and swelling
• Persistent symptoms over 3 months unresponsive to treatment

Special groups. Children: allergic rhinitis with asthma and eczema, adenoidal hypertrophy. Pregnancy: rhinitis of pregnancy; avoid decongestants and some antihistamines. Older adults: drug induced and vasomotor rhinitis.

Allergic

• Seasonal allergic rhinitis, perennial allergic rhinitis, occupational allergic rhinitis, allergic rhinoconjunctivitis

Infective

• Viral rhinitis (common cold, influenza, COVID-19), acute and chronic rhinosinusitis

Non-allergic

• Vasomotor rhinitis, irritant rhinitis, NARES, hormonal rhinitis, rhinitis medicamentosa, drug induced rhinitis
• Gustatory rhinitis, cold air induced rhinitis, atrophic rhinitis

Reflex and physiological

• Photic sneeze reflex, post-prandial and ethanol related sneezing, nasal foreign body, and psychogenic or habitual sneezing

Other

• Nasal polyps, structural deformity, cystic fibrosis, primary ciliary dyskinesia, immunodeficiency
• Opioid withdrawal, neonatal abstinence

Reasoning. History and examination usually suffice. Test for allergy when the diagnosis is uncertain, symptoms are persistent, or specific immunotherapy is considered.

First line. Anterior rhinoscopy and nasal endoscopy. Spirometry or peak flow when asthma is suspected.

Targeted tests. Skin prick tests or serum specific IgE to common aeroallergens (grass, tree and weed pollens, house dust mite, animal dander, moulds), interpreted against the history. Total IgE and eosinophil count have limited value. CT sinuses only for suspected chronic rhinosinusitis or complications. Nasal cytology for NARES (eosinophils in nasal secretions). Workplace challenge for occupational rhinitis.

Limitations. Positive allergy tests do not prove clinical relevance. Negative tests do not exclude local allergic rhinitis.

Allergen and irritant avoidance. Dust mite measures (encasings, hot wash bedding at 60 degrees Celsius), pet avoidance, mould control, pollen avoidance (closing windows, showering after exposure), smoke avoidance, and workplace measures.

Medical treatment.

• Intranasal corticosteroid first line for moderate to severe or persistent disease: mometasone 50 micrograms, 2 sprays to each nostril once daily (maximum 200 micrograms daily), or fluticasone propionate 50 micrograms, 2 sprays to each nostril once daily; start 1 to 2 weeks before the pollen season; review technique.
• Oral non-sedating antihistamine for mild or intermittent symptoms: loratadine 10 mg orally once daily or cetirizine 10 mg orally once daily (5 mg in renal impairment); avoid sedating antihistamines (chlorphenamine) in older adults.
• Intranasal antihistamine: azelastine 0.1 percent, 1 spray to each nostril twice daily.
• Combination of intranasal corticosteroid and intranasal antihistamine for poorly controlled disease.
• Ocular symptoms: olopatadine 0.1 percent eye drops, 1 drop twice daily.
• Saline irrigation.
• Montelukast 10 mg orally at night for allergic rhinitis with asthma.
• Short oral prednisolone course (30 mg daily for 5 to 7 days) for severe flares only.
• Ipratropium bromide 0.03 percent nasal spray, 2 sprays to each nostril two or three times daily for watery rhinorrhoea in non-allergic rhinitis.
• Avoid topical decongestants beyond 3 days.

Allergen immunotherapy. Subcutaneous or sublingual immunotherapy for confirmed allergy with inadequate response to medication, given for 3 years under allergy specialist supervision with adrenaline available for reactions.

Pregnancy. Saline irrigation first; intranasal budesonide or beclometasone; loratadine or cetirizine when needed.

Infective causes. Supportive care.

Monitoring. Review at 4 to 6 weeks for response, and annually in chronic disease. Step down treatment when control is good.

Referral and escalation. Allergy or ENT referral for refractory symptoms after 3 months of adequate treatment, suspected occupational disease, or immunotherapy. ENT within 2 weeks for unilateral symptoms with bleeding or mass.

Admission criteria. Anaphylaxis or acute severe asthma.

Discharge and safety netting. Return for wheeze, throat swelling, difficulty breathing, facial swelling, eye symptoms with pain or reduced vision, or persistent symptoms despite treatment.