What is the management for a patient with an itchy throat and cough, possibly due to allergic rhinitis, who is already taking loratadine (antihistamine) or cetirizine (antihistamine), with a history of asthma or other chronic respiratory conditions?

Management of Itchy Throat and Cough in Patients Already Taking Second-Generation Antihistamines

If you are already taking loratadine or cetirizine for itchy throat and cough without adequate relief, you need to switch to a first-generation antihistamine combined with a decongestant, specifically dexbrompheniramine 6 mg plus pseudoephedrine 120 mg (sustained-release) twice daily, as this is the only evidence-based treatment for upper airway cough syndrome. 1, 2

Why Your Current Treatment Isn't Working

• Second-generation antihistamines like loratadine and cetirizine are ineffective for cough because they lack the anticholinergic properties necessary to reduce upper airway secretions that trigger the cough reflex 1, 2, 3
• Multiple controlled studies have demonstrated that newer antihistamines (terfenadine, loratadine, fexofenadine) with or without decongestants fail to relieve cough associated with upper airway cough syndrome 1, 2
• The itchy throat and cough you're experiencing is most likely upper airway cough syndrome (UACS), previously called postnasal drip syndrome, which requires anticholinergic activity to treat effectively 1, 2

The Correct Treatment Approach

First-Line Therapy: Switch to First-Generation Antihistamine/Decongestant Combination

Recommended regimens (choose one): 1, 2

• Dexbrompheniramine 6 mg + pseudoephedrine 120 mg (sustained-release) twice daily
• Azatadine 1 mg + pseudoephedrine 120 mg (sustained-release) twice daily
• Brompheniramine 12 mg + pseudoephedrine 120 mg (sustained-release) twice daily

How to Start Treatment to Minimize Side Effects

• Begin with once-daily dosing at bedtime for 3-5 days before advancing to twice-daily dosing to minimize daytime sedation 2, 4
• This gradual titration allows your body to adjust to the sedating effects while still providing nighttime symptom relief 2
• Expect improvement within days to 2 weeks of starting treatment 2, 4

Why First-Generation Antihistamines Work When Second-Generation Don't

• The mechanism is anticholinergic, not antihistaminic - first-generation antihistamines reduce nasal secretions through anticholinergic activity restricted to the nasal airways, which decreases the postnasal drip triggering your cough 1, 2, 4
• The combination with a decongestant (pseudoephedrine) causes vasoconstriction that further limits secretory response to inflammatory cytokines 1
• This explains why these older medications consistently outperform newer "non-sedating" antihistamines that lack anticholinergic properties 1, 2

Special Considerations for Patients with Asthma

Since you have a history of asthma, there are additional important points:

Treating Your Upper Airway Will Help Your Asthma

• Adequate treatment of upper airway symptoms improves asthma control - studies show that treating allergic rhinitis/UACS reduces asthma symptoms, improves pulmonary function, and decreases asthma-related hospitalizations 1
• Inadequately controlled upper airway disease contributes to asthma exacerbations and poorer symptom control 1

If Allergic Rhinitis is Confirmed as the Underlying Cause

Once you've established that your symptoms respond to the first-generation antihistamine/decongestant combination, add intranasal corticosteroids (fluticasone, mometasone, or budesonide) to address the underlying allergic inflammation 1, 5

• Intranasal corticosteroids are the most effective medication class for controlling all four major symptoms of allergic rhinitis (sneezing, itching, rhinorrhea, nasal congestion) 1
• They prevent seasonal increases in bronchial hyperresponsiveness and improve asthma control when both conditions coexist 1
• Direct the spray away from the nasal septum to minimize local irritation and bleeding 1

Alternative Add-On Options for Allergic Rhinitis

• Leukotriene modifiers (montelukast) can be added to antihistamines with additive effect, though this combination is generally less effective than intranasal corticosteroids 1
• Nasal cromolyn is another option for allergic rhinitis but requires frequent dosing 1

Important Safety Warnings and Contraindications

Avoid First-Generation Antihistamines If You Have:

• Symptomatic benign prostatic hypertrophy or urinary retention - anticholinergic effects can worsen these conditions 2
• Narrow-angle glaucoma - anticholinergic effects may precipitate acute angle closure 2
• Significant cognitive impairment - sedation may worsen confusion 2

Monitor Carefully If You Have:

• Hypertension - the pseudoephedrine component can occasionally elevate blood pressure, though this is rare in patients with controlled hypertension 1
• Check blood pressure periodically when using combination products with decongestants 2

Other Anticholinergic Side Effects to Expect:

• Dry mouth, constipation, and sedation are common 2
• Performance impairment can occur even without subjective awareness of sedation, affecting work performance and driving 2
• Avoid alcohol and other CNS depressants as they may enhance sedation 2

When to Reassess Your Treatment

If Symptoms Don't Improve After 2 Weeks:

• Consider asthma as the primary cause of your cough, especially if you have wheezing, shortness of breath, or chest tightness 2, 3
• Evaluate for other causes of chronic cough including gastroesophageal reflux disease or chronic bronchitis 1
• Consider referral to an allergist or pulmonologist for further evaluation 1

Red Flags Suggesting Bacterial Sinusitis Rather Than UACS:

• Worsening symptoms after initial improvement (double-worsening pattern) 3
• High fever >39°C (102.2°F) with purulent nasal discharge and facial pain lasting >10 days 3
• In these cases, antibiotics may be indicated, but do not use antibiotics for routine viral upper respiratory infections as they provide no benefit and cause harm 3

Common Pitfalls to Avoid

• Don't continue ineffective second-generation antihistamines - if loratadine or cetirizine haven't worked after continuous use, they won't suddenly become effective 1, 2
• Don't use topical nasal decongestant sprays (oxymetazoline, phenylephrine) for more than 3-5 days - this causes rhinitis medicamentosa (rebound congestion) 1
• Don't assume you need antibiotics - most cases of itchy throat and cough are viral or allergic, not bacterial 3
• Don't skip the decongestant component - the combination of first-generation antihistamine PLUS decongestant is what has been proven effective in controlled trials 1, 2