Physician's Weekly Article - Finding the Right Treatment for Chronic Cough

       Chronic cough is a common condition that is challenging to identify. Effective management involves the diagnosis and treatment of upper airway cough syndrome, asthma, and gastroesophageal reflux disease.

      Chronic cough, a cough that lasts longer than 8 weeks in adults and 4 weeks in children, is one of the leading reasons for physician visits. It is estimated that 10% to 20% of adults experience chronic cough during their lifetime, and the accompanying frustration, irritability, anger, and sleep disturbances. “It’s challenging to diagnose the underlying etiology of chronic cough because it often requires treatment of a few different etiologies and using several different treatment strategies over the course of a few months,” explains Matthew A. Rank, MD. The most common causes of chronic cough are upper airway cough syndrome (UACS, also known as postnasal drip syndrome), asthma, and gastroesophageal reflux disease (GERD). Focusing on diagnosing and treating these conditions is the most effective way to resolve chronic cough, according to a review of evidence by Dr. Rank and colleagues reported in the April 2007 Annals of Allergy, Asthma & Immunology.

      An Evidence-Based Approach Helps Resolve Chronic Cough

      In the study conducted by Dr. Rank and colleagues, the research team reviewed chronic cough guidelines from the American College of Chest Physicians, the British Thoracic Society, and the European Respiratory Society, as well as available studies (primarily prospective non-controlled trials). “Although the data on patients with chronic cough and how best to treat them are limited,” says Dr. Rank, “we found that adults showed a high percentage of cough resolution when physicians focused on the diagnosis and treatment of UACS, asthma, and GERD by following the anatomy of the vagus nerve.” Using this approach, physicians have reported success rates as high as 98%; nine of 12 groups reported success rates of more than 90%. The investigators also found that patients often have multiple causes of chronic cough, which must be treated simultaneously.

      Diagnosing Chronic Cough in Adults

      A diagnosis of chronic cough begins with a thorough history and physical examination. The characteristics of the cough and the presence of sputum is not usually helpful in diagnosis, but Dr. Rank says that asking patients about symptoms consistent with asthma, GERD, or rhinitis may be helpful. “Important considerations in the patient history include use of an angiotensin-converting enzyme inhibitor, and smoking,” he says. “A chest x-ray is not generally useful in determining the cause of the chronic cough, but it can be used to rule out a serious illness. Further testing depends upon the suspected cause of the chronic cough.”

      Treating Chronic Cough

      According to Dr. Rank, empiric treatment for chronic cough is recommended unless the specific cause can be identified and treated (Table 1). “If UACS is the suspected cause, empiric treatment with a first-generation antihistamine decongestant or a nasal steroid is recommended. There is insufficient evidence available to determine which treatment is most effective, but if the specific cause is found, it should be treated. In cough-variant asthma, where chronic cough is the only manifestation of asthma, empiric treatment with either inhaled or systemic corticosteroids is recommended. It should be noted, however, that no data comparing these two therapies are available. Leukotriene modifiers may be considered in step-up therapy. If GERD is the suspected cause of chronic cough, empiric treatment with proton pump inhibition along with lifestyle changes is recommended for 3 months before testing. If necessary, the addition of prokinetic agents may be considered.”

      Chronic Cough in Children

      Even less research is available about chronic cough in children than in adults. “Pediatric chronic cough is not terribly well characterized. There’s still much debate about how often asthma is the cause of chronic cough in children,” says Dr. Rank. Protracted bacterial bronchitis is also believed to be a common cause of chronic cough in children. If a history, physical examination, chest x-ray, and spirometry do not lead to a diagnosis, distinguishing between a wet and dry cough may be helpful (Table 2). “Children with dry cough should receive inhaled corticosteroids for empiric treatment of asthma,” Dr. Rank says. “Children with moist cough should receive antibiotics for presumed protracted bacterial bronchitis. A more detailed workup is necessary for children who fail to respond to steroids or antibiotics.”

      What to Do When Potentially Serious or Difficult Cases Present

      Primary care physicians can successfully treat many patients with chronic cough, but some cases may require a referral to a specialist. “When there is a concern based on initial testing for a serious underlying disorder, or when the patient’s cough persists despite initial treatment attempts, the primary care physician should refer the patient to a sub-specialist,” says Dr. Rank. “Pulmonologists commonly receive these referrals, but otolaryngologists, allergists, and gastroenterologists can be instrumental in diagnosing chronic cough that is suspected due to UACS, asthma, and/or GERD.”

      Matthew A. Rank, MD has indicated to Physician’s Weekly that he has or has had no financial interests to report.