Epidemiological relationships between the common cold and exacerbation frequency in COPD.

Higher exacerbation incidence rates in chronic obstructive pulmonary disease (COPD) are associated with more rapid decline in lung function and poorer quality of life, yet the mechanisms determining susceptibility to exacerbation remain ill-defined. The same viruses responsible for common colds are frequently isolated during exacerbations. The current authors hypothesised that exacerbation frequency may be associated with an increased frequency of colds, and investigated whether increased exacerbation frequency was associated with increased acquisition of colds, or a greater likelihood of exacerbation once a cold has been acquired. A total of 150 patients with COPD completed diary cards recording peak expiratory flow, and respiratory and coryzal symptoms for a median 1,047 days. Annual cold and exacerbation incidence rates (cold and exacerbation frequency) were calculated, and the relationships between these variables were investigated. This analysis is based on 1,005 colds and 1,493 exacerbations. Frequent exacerbators (i.e. those whose exacerbation frequency was greater than the median) experienced significantly more colds than infrequent exacerbators (1.73 versus 0.94.yr(-1)). The likelihood of exacerbation during a cold was unaffected by exacerbation frequency. Patients experiencing frequent colds had a significantly higher exposure to cigarette smoke (46 versus 33 pack-yrs). Exacerbation frequency in chronic obstructive pulmonary disease is associated with an increased frequency of acquiring the common cold, rather than an increased propensity to exacerbation once a cold has been acquired.     

The common cold

Despite great advances in medicine, the common cold continues to be a great burden on society in terms of human suffering and economic losses. Of the several viruses that cause the disease, the role of rhinoviruses is most prominent. About a quarter of all colds are still without proven cause, and the recent discovery of human metapneumovirus suggests that other viruses could remain undiscovered. Research into the inflammatory mechanisms of the common cold has elucidated the complexity of the virus-host relation. Increasing evidence is also available for the central role of viruses in predisposing to complications. New antivirals for the treatment of colds are being developed, but optimum use of these agents would require rapid detection of the specific virus causing the infection. Although vaccines against many respiratory viruses could also become available, the ultimate prevention of the common cold seems to remain a distant aim.     

Antihistamines and the common cold

OBJECTIVE: To determine if antihistamines provided clinically significant relief from the symptoms of the common cold. METHODS: Structured literature review following standardized guidelines of primary studies published after 1975. MEASUREMENTS: Improvements in symptom scores for total symptoms and nasal symptoms over the first three days of a common cold. RESULTS: Three of five studies reporting on sneezing found a statistically significant improvement in the antihistamine group; similarly, three of seven studies reporting on nasal discharge found a statistically significant improvement with therapy. No study reported improvement in total symptom score at the level of p<.05. The validity of these findings was weakened by several flaws in the literature such as inattention to clinical significance and functional impact, inappropriate use of statistical tests, and poorly described methodology. The clinical significance of these improvements was not demonstrated. CONCLUSIONS: The primary literature offers little support for the use of antihistamines in the common cold.     

Cough and the common cold

To determine whether the cough of the common cold arises from upper respiratory stimuli and whether antihistamine-decongestant therapy is an effective treatment for this cough, we prospectively evaluated volunteers with uncomplicated common colds in a randomized, double-blind, placebo-controlled study. After completing a standardized questionnaire and undergoing a physical examination, throat-culturing, and pulmonary function testing, subjects took the active drug or identical-appearing placebo for 7 days while they kept a diary in which they ranked the severity of 17 symptoms for 14 days. Pulmonary function testing was repeated, on average, on Days 4, 8, and 14. Forty-six percent of the variation in cough severity could be explained by throat-clearing and 47% of the variation in throat-clearing severity by postnasal drip. FIF50%, the only physiologic parameter that significantly correlated with cough, rose as cough severity fell. Antihistamine-decongestant therapy reduced postnasal drip and significantly decreased the severity of cough, nasal obstruction, nasal discharge, and throat-clearing during the first few days of the common cold. In addition, cough was 20 to 30% less prevalent in the active drug group within 3 days of starting therapy. We conclude that the cough of the common cold arose from upper respiratory tract stimuli and that cough and other cardinal symptoms of the common cold were reduced with antihistamine-decongestant therapy when these symptoms were at their worst.     

Pulmonary imaging and function in the common cold

The common cold is generally considered to be an upper respiratory tract infection. We studied the lower respiratory tract in 76 otherwise healthy young adults with the common cold. Viral infection was diagnosed in 56 (74%) of the 76 subjects. Rhinovirus was detected in 42 (55%) subjects. Chest radiography (CR) and high-resolution computerized tomography (HRCT) were carried out in 40 subjects on day 7, and pulmonary function testing with bronchodilator challenge was carried out in 36 patients on days 7 and 21 of the study. Clinical examinations were carried out on days 1, 7 and 21. The subjects recorded their symptoms on a diary card for 20 d. The mean duration of cough was 8.4 (SD 6.5) d and that of sputum production 5.9 (SD 6.4) d. No abnormal findings were detected in the lungs on auscultation. CR and HRCT showed no pulmonary changes associated with the common cold. No clinically remarkable increases were seen in peak expiratory flow, forced expiration volume in 1 s or forced vital capacity after bronchodilator challenge on either days 7 or 21. All patients made a clinical recovery without antimicrobial therapy within 21 d. We conclude that the common cold in young otherwise healthy adults is an upper respiratory tract infection and that clinically important abnormalities in the lower respiratory tract are rare.