In a 29‑year‑old male with a 5‑day productive cough, mild leukocytosis (white blood cell count 11.0 ×10⁹/L), low monocyte percentage (2.8%), elevated platelet count (411 ×10⁹/L), boggy cobblestoned tonsils, normal vital signs, and no improvement on acetylcysteine, paracetamol, vitamin C and zinc, what is the most likely diagnosis and what are the appropriate next steps?

Most Likely Diagnosis: Upper Airway Cough Syndrome (UACS) with Possible Viral Upper Respiratory Infection

The most likely diagnosis is Upper Airway Cough Syndrome (UACS) secondary to viral rhinopharyngitis, given the 5-day productive cough, congested boggy tonsils with cobblestoning, normal vital signs, and mild leukocytosis consistent with viral infection. 1

Clinical Reasoning

Why UACS is the Primary Diagnosis

• Cobblestoning of the posterior pharyngeal wall is a hallmark physical finding of UACS, representing inflammation from post-nasal drainage 1
• The productive cough with boggy, congested tonsils and cobblestoning strongly suggests upper airway inflammation with post-nasal drip 1
• Approximately 20% of patients have "silent" UACS with no obvious nasal symptoms yet still respond to treatment—this patient may fall into this category 1
• UACS accounts for 18.6%–81.8% of chronic cough cases and is the single most common cause of chronic cough in adults 1

Laboratory Interpretation

• WBC 11.04 × 10⁹/L represents mild leukocytosis consistent with viral infection rather than bacterial infection 2
• The mildly elevated platelet count (411) can occur with inflammation and metabolic factors, and is not specific for infection 3
• The low monocyte percentage (2.8%) is a minor finding that does not significantly alter the clinical picture 2
• The absence of significant leukocytosis (WBC >15), fever, or systemic toxicity argues strongly against bacterial pneumonia or serious bacterial infection 4, 2

Why This is NOT Bacterial Pharyngitis

• Streptococcal pharyngitis typically presents with abrupt onset, intense sore throat, fever, chills, and tender anterior cervical lymph nodes with pharyngeal exudate 5
• This patient has non-erythematous tonsils, which argues against acute bacterial pharyngitis 5
• The productive cough is uncommon in streptococcal pharyngitis—cough, coryza, and conjunctivitis suggest a viral cause 5
• Normal vital signs and absence of fever make bacterial infection less likely 4

Next Steps: Evidence-Based Management Algorithm

Immediate Management (Week 1)

1. Discontinue ineffective current medications and initiate UACS-directed therapy:

• Start a first-generation antihistamine/decongestant combination immediately (e.g., chlorpheniramine 4 mg + sustained-release pseudoephedrine 120 mg twice daily) 1

  • This is the most effective evidence-based first-line treatment for UACS 1
  • Improvement typically occurs within days to 1–2 weeks 1
  • To minimize sedation, consider starting with once-daily dosing at bedtime for a few days before increasing to twice-daily 1

• Add intranasal corticosteroid spray (fluticasone propionate 100–200 mcg daily, 1–2 sprays per nostril) 1

  • Intranasal corticosteroids are the most effective monotherapy for both allergic and non-allergic rhinitis-related UACS 1
  • A full 1-month trial is necessary to assess response 1

• Recommend high-volume saline nasal irrigation (150 mL per nostril, twice daily) 1

  • More effective than saline spray because irrigation better expels secretions 1
  • Improves mucociliary function and mechanically removes inflammatory debris 1

2. Symptomatic relief for cough:

• Continue acetylcysteine 600 mg for mucolytic effect if tolerated
• Add dextromethorphan 15–30 mg every 6–8 hours as needed for cough suppression 1
• Honey and lemon for symptomatic relief 6

3. Supportive care:

• Adequate hydration 6
• Paracetamol 500 mg every 4–6 hours as needed for discomfort (continue current regimen)
• Adequate rest 6

Critical: What NOT to Do

• Do NOT prescribe antibiotics—this is a viral upper respiratory infection with UACS, and antibiotics have no role and contribute to antimicrobial resistance 1, 6
• Do NOT use topical nasal decongestants (oxymetazoline, xylometazoline) for more than 3–5 consecutive days due to risk of rhinitis medicamentosa 1
• Do NOT use newer-generation antihistamines (cetirizine, loratadine, fexofenadine) alone—they are ineffective for non-allergic UACS 1

Follow-Up and Reassessment (Week 2–3)

If symptoms improve: Continue treatment for full course (minimum 2–4 weeks for intranasal corticosteroids) 1

If no improvement after 1–2 weeks of adequate UACS treatment:

1. Reassess for alternative or coexisting diagnoses 1:

   • Asthma/cough-variant asthma: Consider bronchoprovocation testing or empiric trial of inhaled corticosteroids 7, 1
   • GERD: Initiate high-dose PPI (omeprazole 20–40 mg twice daily before meals) for at least 8 weeks with dietary modifications 1
   • Post-infectious cough: If cough persists 3–8 weeks, add inhaled ipratropium bromide 2–3 puffs four times daily 6

2. Consider sinus imaging (CT) if persistent purulent nasal discharge, facial pain, or pressure develops 1

Red Flags Requiring Immediate Re-Evaluation

Instruct the patient to return immediately if: 4

• Fever develops or persists >4 days
• Hemoptysis occurs
• Dyspnea or respiratory distress develops
• Focal chest signs appear (crackles, dullness, bronchial breathing)
• Progressive symptom worsening
• Weight loss or night sweats develop

If Cough Persists Beyond 8 Weeks

• Reclassify as chronic cough and systematically evaluate for UACS, asthma, and GERD 7, 1
• Obtain chest radiograph to exclude structural lung disease, malignancy, or tuberculosis 7, 4
• Consider referral to pulmonology for bronchoscopy if all empiric therapies fail 1

Common Pitfalls to Avoid

• Do not rely solely on physical examination—the absence of visible post-nasal drainage or cobblestoning does not rule out UACS 1
• Do not overlook "silent" UACS as a cause before investigating less common etiologies 1
• Do not confuse GERD with UACS—both can cause pharyngeal inflammation and may coexist 1
• Do not prescribe antibiotics for viral URTI with UACS—this provides no benefit and causes harm 1, 6
• Chronic cough is frequently multifactorial—maintain all partially effective treatments rather than discontinuing them prematurely 1

Summary of Immediate Action Plan

1. Start first-generation antihistamine/decongestant combination (e.g., chlorpheniramine + pseudoephedrine) 1
2. Add intranasal fluticasone 100–200 mcg daily 1
3. Recommend high-volume saline nasal irrigation twice daily 1
4. Continue supportive care (hydration, paracetamol, rest) 6
5. Add dextromethorphan for cough suppression as needed 1
6. Reassess in 1–2 weeks—if no improvement, proceed with sequential evaluation for asthma and GERD 1
7. Provide clear return precautions for red-flag symptoms 4