What is the treatment for a severe dry cough due to dust allergy?

Treatment Prescription for Severe Dry Cough Due to Dust Allergy

For severe dry cough caused by dust allergy, start with a first-generation antihistamine combined with a decongestant (such as dexbrompheniramine 6 mg twice daily plus pseudoephedrine 120 mg twice daily), as this combination is specifically proven effective for upper airway cough syndrome from allergic rhinitis. 1

Primary Treatment Approach

First-Line Therapy: Antihistamine/Decongestant Combination

• Prescribe a first-generation antihistamine plus decongestant combination as the initial treatment for dust allergy-induced cough 1, 2
• Specific regimens proven effective include:
  • Dexbrompheniramine maleate 6 mg twice daily PLUS pseudoephedrine sulfate 120 mg (sustained-release) twice daily 1
  • Azatadine maleate 1 mg twice daily PLUS pseudoephedrine sulfate 120 mg (sustained-release) twice daily 1
• First-generation antihistamines work better than newer non-sedating antihistamines for this condition due to their anticholinergic properties that reduce secretions 1
• Expect improvement within days to 2 weeks of starting therapy 1

Add Nasal Corticosteroid for Enhanced Control

• Add intranasal corticosteroid spray (such as fluticasone propionate 200 mcg daily - two 50-mcg sprays per nostril once daily) for comprehensive control of allergic rhinitis and associated cough 1, 3, 4
• Nasal corticosteroids significantly improve daytime cough severity in dust allergy patients 4
• Maximum effect may take several days but some improvement can occur within 12 hours 3

Environmental Control Measures (Essential Adjunct)

Implement multicomponent dust mite avoidance strategies, as single interventions are ineffective 1:

Bedroom Interventions (Highest Priority)

• Encase pillows in fine weave or vapor-permeable covers (less than 10 μm pore) 1
• Encase mattresses in vapor-permeable or plastic covers 1
• Encase box springs in vinyl or plastic 1
• Wash all bedding weekly in hot water (130°F/54°C) 1
• Remove stuffed animals and toys from the bed 1

Household Interventions

• Vacuum weekly wearing a mask; leave the room for 20 minutes after cleaning 1
• Use vacuum cleaner with double-thickness bags or HEPA filter 1
• Replace carpets with polished wood flooring if feasible 1
• Replace upholstered furniture with leather, vinyl, or wood 1

Symptomatic Relief Options

For Persistent Cough Despite Above Measures

• Dextromethorphan 60 mg provides maximum cough reflex suppression with prolonged effect 5
• Dextromethorphan is more effective than codeine with fewer side effects 5
• Honey and lemon mixtures can provide additional symptomatic relief 1, 5
• Menthol lozenges offer short-term cough suppression 5

Important Clinical Considerations

What NOT to Prescribe

• Avoid newer-generation antihistamines alone (terfenadine, loratadine) as monotherapy for cough - they are ineffective for this specific indication despite working for rhinitis symptoms 1, 6, 7
• Do not prescribe antibiotics - they provide no benefit for allergy-related cough 5
• Avoid expectorants, mucolytics, or bronchodilators for this dry cough 5

Common Pitfalls to Avoid

• Do not treat only the nasal symptoms - the cough requires the anticholinergic effect of first-generation antihistamines specifically 1
• Do not rely on antihistamines alone without environmental control measures, as multicomponent interventions are necessary for dust mite allergy 1
• Do not expect immediate results - allow 2 weeks for full therapeutic effect 1

When to Reassess or Refer

• If no improvement after 2 weeks of appropriate therapy, consider alternative diagnoses 2
• Rule out asthma if cough persists, as dust mite allergy can trigger both upper and lower airway disease 1
• Consider allergy testing to confirm dust mite sensitization if not already performed 1

Prescription Summary

Rx #1: Dexbrompheniramine 6 mg + Pseudoephedrine SR 120 mg tablets
Sig: Take 1 tablet by mouth twice daily (morning and evening)

Rx #2: Fluticasone propionate nasal spray 50 mcg/spray
Sig: Spray 2 sprays in each nostril once daily

Rx #3: Dextromethorphan 30 mg tablets (for breakthrough cough)
Sig: Take 1-2 tablets by mouth as needed for severe cough (maximum 60 mg per dose)

Non-prescription: Implement complete dust mite avoidance protocol as detailed above