Why use nasal sprays for chronic cough?

Nasal Sprays for Chronic Cough: Role and Effectiveness

Nasal corticosteroid sprays are recommended for chronic cough when upper airway cough syndrome (UACS) or post-nasal drip is the underlying cause, as they effectively target the inflammation that leads to post-nasal secretions and subsequent cough. 1

Understanding Upper Airway Causes of Chronic Cough

Chronic cough (lasting more than 8 weeks) is commonly caused by:

1. Upper Airway Cough Syndrome (UACS) - Previously called post-nasal drip syndrome
2. Asthma
3. Gastroesophageal reflux disease (GORD)
4. Chronic bronchitis
5. Non-asthmatic eosinophilic bronchitis

UACS is reported as one of the most common causes of chronic cough, particularly in the American literature 1. It involves nasal secretions draining into the posterior pharynx, triggering the cough reflex.

How Nasal Sprays Help with Chronic Cough

Mechanism of Action

• Intranasal corticosteroids (like fluticasone propionate) work directly in the nasal passages to:
  • Reduce inflammation
  • Decrease mucus production
  • Act on multiple inflammatory substances (histamine, prostaglandins, cytokines, tryptases, chemokines and leukotrienes) 2, 3
  • Reduce post-nasal drip that triggers cough

Evidence for Effectiveness

• Topical nasal steroids given for 2-8 weeks have been shown to be effective in treating cough associated with post-nasal drip 1
• Intranasal corticosteroids are particularly effective for cough due to allergic rhinitis 2
• One randomized placebo-controlled trial demonstrated that intranasal steroids given for 2 weeks effectively treated cough due to allergic rhinitis 1

Treatment Recommendations

First-Line Treatment for UACS-Related Cough

1. Intranasal corticosteroids (e.g., fluticasone propionate):

   • Dosage: Once daily in the morning 4
   • Duration: At least 2-8 weeks 1
   • Note: May take several days to reach maximum effect 3

2. First-generation antihistamine/decongestant combinations:

   • Recommended in the USA as first-line approach 1
   • Note: First-generation antihistamines may not be available in all countries

Treatment Algorithm

1. For patients with obvious UACS symptoms:

   • Begin with intranasal corticosteroids 1, 2
   • Evaluate response after 3-5 days
   • If minimal improvement after 10-14 days, consider changing therapy 2
   • For partial response, continue treatment for another 10-14 days 2

2. For patients without obvious cause of chronic cough:

   • Consider empiric trial of therapy for UACS 1
   • If no response to empiric therapy, proceed with sinus imaging 1

Important Considerations

• Duration of treatment: Complete resolution of cough may take several weeks to months; premature discontinuation may lead to treatment failure 2

• Potential pitfalls:

  • Overuse of antibiotics (most cases of rhinosinusitis are viral, not bacterial) 2
  • Relying on mucus color to dictate antibiotic use is not recommended 2
  • Using decongestants alone will only relieve nasal congestion but not cough 2
  • Prolonged use of topical decongestants can lead to rhinitis medicamentosa 2

• Non-pharmacological approaches:

  • Adequate hydration
  • Warm facial packs
  • Sleeping with head elevated
  • Avoiding irritants (cigarette smoke, pollution, allergens) 2

Special Populations

• Elderly patients: Monitor for dehydration and consider nutritional support if oral intake is poor 2
• Children under 6: First-generation antihistamine/decongestant combinations not recommended due to safety concerns 2

Remember that chronic cough often has multiple contributing causes, and nasal sprays are just one component of what may need to be a comprehensive treatment approach targeting the specific underlying cause(s).