What are the potential causes and management options for a patient with a severe cough and no fever, considering their age, medical history, and lifestyle?

Severe Cough Without Fever: Evaluation and Management

For a patient with severe cough and no fever, first determine the duration: if less than 3 weeks (acute), treat empirically for upper respiratory infection with first-generation antihistamine/decongestant; if 3-8 weeks (subacute), treat as post-infectious cough; if greater than 8 weeks (chronic), systematically evaluate and treat the four most common causes in sequential additive steps. 1

Duration-Based Classification

The absence of fever significantly narrows your differential and guides management:

• Acute cough (< 3 weeks): Most commonly viral upper respiratory infection, though lack of fever makes bacterial pneumonia less likely 1
• Subacute cough (3-8 weeks): Post-infectious cough is the leading diagnosis (48.4% of cases), followed by upper airway cough syndrome (33.2%) and asthma (15.8%) 1
• Chronic cough (> 8 weeks): Four conditions account for 90% of cases—upper airway cough syndrome, asthma, gastroesophageal reflux disease, and nonasthmatic eosinophilic bronchitis 2, 3

Critical Red Flags Requiring Immediate Evaluation

Even without fever, screen for these concerning features that demand urgent workup:

• Hemoptysis (pulmonary embolism causes cough in nearly half of cases) 1, 4
• Smoker > 45 years with new or changed cough 1
• Adults 55-80 years with ≥30 pack-year smoking history 1, 5
• Prominent dyspnea, especially at rest or night 1
• Systemic symptoms or weight loss 1, 4
• Abnormal chest radiograph 1

Initial Management Algorithm

Step 1: Medication Review

Immediately discontinue ACE inhibitors if the patient is taking one, regardless of temporal relationship—these cause chronic dry cough in 5-50% of patients, with median resolution time of 26 days after stopping. 1, 4, 6

Step 2: Smoking Status

If currently smoking, smoking cessation is the priority intervention, with 90-94% reporting cough resolution, typically within 4 weeks. 1, 4, 5

Step 3: Duration-Specific Treatment

For Acute Cough (< 3 weeks):

• First-generation antihistamine plus decongestant (e.g., diphenhydramine 25-50mg + pseudoephedrine 60mg, three to four times daily) has been shown in double-blind placebo-controlled studies to decrease cough severity and hasten resolution 1, 7
• Consider naproxen, which favorably affects cough in controlled trials 1

For Subacute Cough (3-8 weeks):

• Treat as post-infectious cough with first-generation antihistamine/decongestant combination, as most resolve within this timeframe 7
• Dextromethorphan-containing suppressants are more effective than other cough suppressants for symptomatic relief 7, 8
• If no preceding respiratory infection, evaluate and manage as chronic cough 1

For Chronic Cough (> 8 weeks): Treat the four most common causes in sequential and additive steps—do not stop after identifying one cause, as 59% have multiple simultaneous contributors: 1, 5, 2

1. Upper Airway Cough Syndrome (UACS): First-generation antihistamine/decongestant combination 1, 6

2. Asthma: Inhaled corticosteroids with or without bronchodilators, even without spirometric evidence of obstruction 4, 2

3. Gastroesophageal Reflux Disease: Intensive acid suppression (PPI) for at least 3 months plus diet/lifestyle modifications 1, 4

4. Nonasthmatic Eosinophilic Bronchitis: Inhaled corticosteroids 1, 2

Essential Diagnostic Testing

• Chest radiograph is mandatory for chronic cough to rule out malignancy, tuberculosis, and other serious conditions 1, 6
• Spirometry (pre- and post-β2 agonist) when age-appropriate to assess for asthma or COPD 1
• Do not routinely perform additional tests (skin prick, CT, bronchoscopy) unless clinical symptoms and signs specifically indicate them 1

Common Pitfalls to Avoid

Do not use empirical treatment for upper airway cough syndrome, GERD, or asthma unless other features consistent with these conditions are present—this shotgun approach is specifically discouraged by guidelines. 1

Maintain all partially effective treatments due to the high likelihood of multiple simultaneous causes (59% of cases). 1, 5

For patients with chronic bronchitis history, maintain a low threshold for imaging when cough character changes, particularly in those meeting lung cancer screening criteria. 5

Symptomatic Management for Severe Cough

While treating the underlying cause:

• Central acting antitussives (codeine or dextromethorphan) reduce cough counts by 40-60% for severe paroxysms 4, 8
• NSAIDs or acetaminophen for associated musculoskeletal chest pain (occurs in up to 82.4% with severe coughing) 4
• Avoid guaifenesin if cough is chronic as occurs with smoking, asthma, chronic bronchitis, or emphysema per FDA labeling 9

Follow-Up and Reassessment

Routinely follow up in 4-6 weeks and assess cough severity or quality of life with validated tools before and after treatment. 1

If empirical trials are used, define a limited duration to confirm or refute the hypothesized diagnosis rather than continuing indefinitely. 1

For refractory chronic cough after systematic evaluation and treatment, consider referral to pulmonology and trials of gabapentin, pregabalin, or speech therapy. 2, 3, 10