A tertiary care center approximately 175 miles away from the source of a California wildfire in late 2018 and early 2019 saw an increase in the number of patient visits for atopic dermatitis (AD) and pruritis, according to recent research published in JAMA Dermatology.
“These results highlight an association between air quality and skin health, which may assist clinicians and public health practitioners to better understand the prevention and treatment of cutaneous diseases and the associated health care use rates,” Raj P. Fadadu, MS, of the Department of Dermatology at the University of California, San Francisco, and colleagues wrote in their study.
Mr. Fadadu and colleagues performed a cross-sectional time-series study of 4,147 patients (8,049 visits) from dermatology clinics in San Francisco associated with an academic tertiary care hospital system between October 2018 and February 2019 and compared those visits to a timeframe when there were no wildfires near the clinics between October 2015 and February 2016. Patients in the study were children (mean 7.5 years old) and adults (mean 51.9 years old) who had either AD or pruritis prior to, during, and after the California Camp Fire in 2018. The researchers analyzed air pollution associated with the wildfire by fire status, smoke plume density scores derived from satellites, and concentration of particulate matter less than 2.5 μm in diameter.
After adjusting for factors such as temperature, humidity, age, and patient volume, the results showed visits for AD were 1.49 times higher during the wildfire for children (95% confidence interval, 1.07-2.07) and 1.15 times higher for adult patients (95% CI, 1.02-1.30) than in 2015 and 2016. Visits for itch were 1.82 times higher for children (95% CI, 1.20-2.78) and 1.29 times higher for adults (95% CI, 0.96-1.75) during 2015 and 2016, and the researchers noted a 10-μg/m3 increase in mean PM2.5 concentration per week increased weekly pediatric visits to a dermatology clinic for pruritis by 7.7% (95% CI, 1.9-13.7%). Regarding medication use during the wildfire, prescribed systemic medications had an adjusted rate ratio for adults of 1.45 (95% CI, 1.03-2.05).
In a related editorial, Kenneth W. Kizer, MD, MPH, of Atlas Research LLC in Washington, DC, said the results by Fadadu et al were “consistent with data reported from exposure to air pollution from other sources.” However, he noted that the authors did not account for non-dermatology clinics that might have seen these patients, including primary care facilities, for “air pollution–sensitive skin conditions,” such as acne and psoriasis, and suggested that the study “captured only a small portion of the smoke-related skin health morbidity resulting from the Camp Fire.”
“Given the millions of Californians who were exposed to the Camp Fire’s drifting smoke and the population prevalence of atopic dermatitis (as high as 20% in children and 10% in adults) and extrapolating from the increased incidence of atopic dermatitis and itch reported by Fadadu et al, it is likely that many thousands of people developed smoke-related skin health problems,” he said.
Another consideration of the study, Dr. Kizer said, is that the generalizability of the findings is uncertain because smoke from wildfires can differ based on where and what the fire burns.
“As a result of the varying composition of smoke and changes in its composition that may occur in the atmosphere, as well as the varying degrees and durations of smoke exposure, the health consequences of smoke pollution are less predictable than exposure to air pollution from traffic and industrial sources,” he explained. “The harmful effects of wildfire smoke pollution from different wildfires may vary substantially.”
As climate change will likely worsen the occurrence of wildfires, “it should be expected that the health care burden of atopic dermatitis and other air pollution–sensitive skin diseases will grow substantially in coming years,” Dr. Kizer concluded. “Improved pharmacologic treatments and other interventions for these conditions will be helpful in addressing this growing problem, but more effective policies and practices to mitigate climate change and reduce wildfires will be even more helpful.”