Treatment of postviral nonasthmatic cough with corticosteroids.

TO THE EDITOR: Postviral cough is a common problem, affecting approximately 5% of the population annually. Cough is the most common symptom leading patients to offices of primary care physicians. Antibiotics, antitussives, mucolytics, b-agonists, and inhaled corticosteroids have only limited efficacy in the treatment of postviral cough. The modest cough suppression of the latter two agents might be indicative of occasionally undiagnosed reactive airway disease. The usual therapies for managing acute postviral cough have been shown to be ineffective. The symptoms typically persist for approximately 3 weeks. However, a cough may be prolonged for 8 weeks (subacute) or longer (chronic cough). The lack of effective treatments may prompt some frustrated physicians to the empiric use of antibiotics, which may lead to the possibility of developing resistant organisms and allergies. However, not treating these patients with antibiotics often results in an equally frustrated patient who will then seek help elsewhere to obtain a frequently expensive and ineffective treatment for a viral infection. Although viruses are responsible for 90% of postinfectious coughs, approximately two-thirds of patients in the United States diagnosed with this entity are treated with antibiotics. A recent article reports that the greatest risk to human health comes in the form of antibiotic-resistant bacteria. Although other factors are involved, their inappropriate use can result in antibiotic resistant infections. While the use of oral corticosteroids seems reasonable for a troublesome cough, no previous clinical data have been presented to support the use of oral corticosteroids in patients with postviral cough who do not have asthma. In this case series of eight patients with histories of recurrent postviral nonasthmatic coughs, the cough was markedly improved by treatment with oral corticosteroids, supporting this modality of treatment for this troublesome condition. All patients with histories of recurrent coughs after upper respiratory infections and no evidence of asthma seen over the past 8 years are included in this series. Eight patients presented with a postviral nonproductive cough that lasted from 4 days to 3 months (Table I). Except for patient JF, all were nonsmokers, and none were taking angiotensin-converting enzyme inhibitors. Previously, they had been treated with one or more of the following: antibiotics (frequently more than once), antitussives, mucolytics, b-agonists, and inhaled corticosteroids, with no significant decrease in the cough. Physical examinations, except for swelling of the nasal turbinates, were entirely within normal limits in all of the patients. Specifically, on auscultation of the chest no wheezing, rhonchi, or rales was heard. Cough was induced on forced expiration. Vital signs were within normal limits. The pulse oximetry was 99% or 100% in all patients. Pulmonary function tests were performed with a Puritan Bennett Spirometer 900 (Wilmington, Mass). All test results were within normal limits (Table II). Because many patients with recurrent bronchitis may have unrecognized asthma, cough variant asthma was considered, and a methacholine challenge test was performed on all patients by means of a modification of the protocol described by Catham et al with the use of a nebulizer for the inhalation of methacholine. This modified screening methacholine challenge method correlated with results obtained from the traditional lengthy protocol and correctly identified levels of airway reactivity in all subjects. The screening challenge consisted of one breath followed by four breaths of a 5 mg/mL methacholine solution. Subsequently, the protocol included one breath and then four breaths of a 25 mg/mL methacholine solution. Spirometric tests were performed after each inhalation. The solutions were delivered via a DeVilbiss Pulmo-Aide nebulizer (Somerset, Pa). The methacholine challenges would be terminated if the FEV1 decreased by more than 20% from the baseline, the determining factor for a positive methacholine challenge (indicative of asthma). In these eight patients, the FEV1 decreased an average of "9% with a range from "7% to "11%, and the FVC decreased an average of "2.68% with a range from 2% to "8% (Table II). The negative methacholine challenges supported the conclusion that these patients did not have asthma. The patients were treated with 25 to 50 mg of prednisone per day for 5 to 7 days with resolution of the cough within 1 week in all patients (Table II). No clinical data support the use of inhaled or oral corticosteroids for the treatment of postviral induced cough in patients without asthma. Although the positive predictive value for methacholine challenge ranges from 60% to 88%, the negative predictive value is considered to be 100%. The sensitivity of the methacholine challenge in ruling out asthma, coupled with the fact that the patients did not report a history of wheezing, chronic cough, or exercise-induced dyspnea strongly suggests that none of the patients in the current series had asthma. They only reported a cough after upper respiratory infections, which are invariably viral. The only other clinical entity characterized by a cough and a negative methacholine challenge and responsive to corticosteroids is an entity known as eosinophilic bronchitis. The distinguishing feature in patients with this condition from those in this report is that patients with eosinophilic bronchitis must remain on long-term corticosteroids for symptom control, whereas the patients presented here are entirely symptom free between episodes of postviral cough without the need for chronic corticosteroids. In recent years, the concept has been evolving that postviral coughs reflect an inflammatory response to infection. Specifically, the inflammatory response affects the epithelium of the bronchi with epithelial cell desquamation and denuding of the airway to the level of the basement membrane. These findings