What is the appropriate workup for a patient presenting with a dry cough?

From the Guidelines

The appropriate workup for a patient presenting with a dry cough begins with a thorough history and physical examination to determine the likely cause, as recommended by the American College of Chest Physicians 1. Key history elements include:

• Duration of symptoms
• Associated symptoms (fever, shortness of breath, postnasal drip)
• Exacerbating factors
• Smoking status
• Medication use (particularly ACE inhibitors)
• Exposure history Physical examination should focus on:
• Vital signs
• Lung auscultation
• Cardiac examination
• Assessment for postnasal drip Initial diagnostic testing may include:
• Chest X-ray to rule out pneumonia, lung masses, or other structural abnormalities
• For coughs lasting more than 8 weeks, additional testing may include:
  • Pulmonary function tests to assess for asthma or COPD
  • CT scan of the chest for more detailed lung imaging
  • Potentially bronchoscopy if a specific lesion requires evaluation Laboratory tests might include:
• Complete blood count to check for infection or eosinophilia
• Specific tests based on clinical suspicion such as:
  • Sputum cultures
  • FeNO testing for eosinophilic inflammation
  • Allergy testing Management depends on the underlying cause, ranging from:
• Treating GERD with proton pump inhibitors (such as omeprazole 20mg daily) 1
• Addressing postnasal drip with antihistamines (like loratadine 10mg daily) or nasal steroids (fluticasone 1-2 sprays per nostril daily)
• Using inhaled corticosteroids (such as budesonide 180mcg twice daily) for asthma For symptomatic relief while determining the cause, options include:
• Dextromethorphan 10-30mg every 4-6 hours
• Benzonatate 100-200mg three times daily Persistent cough without clear cause after initial workup warrants referral to pulmonology, ENT, or allergy specialists, as suggested by the 2018 Chest guideline and expert panel report 1. In patients with unexplained chronic cough, a therapeutic trial of multimodality speech pathology therapy may be suggested, as well as a therapeutic trial of gabapentin, as recommended by the 2016 Chest guideline and expert panel report 1. It is also important to consider the patient's quality of life and to address any potential underlying conditions that may be contributing to the cough, as emphasized by the 2019 Chest guideline and expert panel report 1.

From the Research

Workup for Dry Cough

The workup for a patient presenting with a dry cough involves a comprehensive approach to determine the underlying cause.

• A focused history and physical examination are essential in the initial evaluation, as they can provide clues about the cause of the cough 2, 3, 4.
• Chest radiography is a crucial diagnostic tool in the workup of patients with chronic cough, as it can help identify underlying conditions such as tuberculosis, chronic fungal infection, bronchiectasis, or lung abscess 2, 5.
• The most common causes of chronic cough in adults are upper airway cough syndrome, asthma, and gastroesophageal reflux disease, alone or in combination 2, 4.
• In children, a cough lasting longer than four weeks is considered chronic, and the most common causes are respiratory tract infections, asthma, and gastroesophageal reflux disease 2.
• Further testing, such as high-resolution computed tomography, and referral to a pulmonologist may be indicated if the cause of chronic cough is not identified 2.
• A trial of a decongestant and a first-generation antihistamine is warranted if upper airway cough syndrome is suspected, while empiric treatment for gastroesophageal reflux disease should be initiated in lieu of testing for patients with chronic cough and reflux symptoms 2.
• The diagnosis of asthma should be confirmed based on clinical response to empiric therapy with inhaled bronchodilators or corticosteroids 2.
• Patients should avoid exposure to cough-evoking irritants, such as cigarette smoke 2.

Diagnostic Approach

• A comprehensive history and physical examination can suggest the correct diagnosis, and specific therapy can be directed to the underlying disease 5.
• Pulmonary function studies are often helpful in the workup of the patient with chronic cough, as they can help identify patterns of obstructive or restrictive lung disease 5.
• Bronchoprovocation testing can be helpful when baseline pulmonary function tests are normal and the diagnosis of postviral bronchitis or cough-variant asthma is suggested 5.
• The use of diagnostic tests, including methacholine challenge, gastroesophageal reflux studies, and sinus imaging, is based on clinical suspicion 4.
• A detailed history and evaluation are necessary to reach a diagnosis and provide successful treatment for patients with dry cough 6.