Lung function tests and risk factors for pneumonia in adults with chickenpox

Varicella is 25 times more likely to be complicated by pneumonia in adults than in children. Data on changes in lung function following pneumonia are limited. This study was undertaken to describe the epidemiological factors associated with pneumonia and to investigate lung function up to 1 year following chickenpox.

Thirty eight consecutive suitable patients admitted to a university hospital were enrolled in the study; 19 had pneumonia and 19 did not. Epidemiological data and density of rash were recorded, spirometric tests were performed, and carbon monoxide transfer factor was measured.

Varicella pneumonia was associated with the presence of respiratory symptoms (p=0.006), current smoking (p=0.003), and history of close contact (p=0.009). There was a trend towards patients with pneumonia having a more severe rash. No association was observed between pneumonia and age or sex. Current smokers had a higher mean number of spots than non-smokers (p=0.005). Carbon monoxide transfer factor at hospital discharge was reduced in 27 patients (71%), more markedly in the group with pneumonia (p=0.009). Nine patients (seven with pneumonia) still had a reduced carbon monoxide transfer factor (mean reduction 36%) at 12 months.

Chickenpox may result in a defect in carbon monoxide transfer factor for at least a year after acute illness.