Wildfires prompt more visits to clinics for atopic dermatitis, itch among older adults
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Clinics visits for itch and atopic dermatitis increased among adults aged 65 years and older during the California Camp Fire in 2018 compared with weeks without wildfire, according to a research letter published in JAMA Network Open.
These statistically significant increases in visit rates among older patients — which did not occur for younger adults — could have been driven by their vulnerability to air pollution, Raj P. Fadadu, MS, student in the department of dermatology at the University of California, San Francisco, and colleagues wrote.
The researchers began with three metrics characterizing air pollution in San Francisco: fire status, indicating whether a wildfire occurred during a particular week; concentration of particulate matter with diameters of 2.5 µm or smaller (PM2.5); and smoke plume density.
For example, the researchers noted that the California Camp Fire increased mean weekly concentrations of PM2.5 in San Francisco by a factor of nine between Nov. 8 and 21, 2018, even though the fire was 175 miles away from the city.
Also, the researchers collected data from outpatient dermatology visits at an academic medical center in San Francisco for AD or itch between Oct. 18, 2018, and Feb. 10, 2019.
The researchers additionally collected data from Oct. 1, 2015, to Feb. 10, 2016, and from Oct. 1, 2016, to Feb. 10, 2017, which were used as control groups since there were no fires during these periods.
The study involved 5,529 adult visits for AD and 1,319 adult visits for itch by 3,448 unique patients (67.4% women; mean age, 44.6 years; standard deviation, 21.1 years).
During weeks with a wildfire, adults aged 65 years and older had adjusted rates of clinic visits that were 1.6 (95% CI, 1.1-2.5) greater for itch and 1.4 (95% CI, 1.1-1.9) greater for AD compared with weeks without a wildfire. Adults aged 18 to 64 years had corresponding rates of 1.1 (95% CI, 0.8-1.7) for itch and 1.1 (95% CI, 1-1.3) for AD.
Also among adults aged 65 years and older, each 1-unit increase in the mean weekly smoke plume density score was associated with a 1.4 (95% CI, 1.1-1.9) times higher rate of clinic visits for itch and a 1.3 (95% CI, 1.1-1.6) times higher rate of clinic visits for AD.
Adults aged 18 to 64 years did not have any change in their rates of clinic visits for itch associated with smoke plume density scores, with a 1.2 (94% CI, 1.1-1.3) higher rate of clinic visits for AD.
Results based on PM2.5 exposure were similar, the researchers continued.
Based on these findings, the researchers concluded that short-term exposure to air pollution from wildfires significantly increased rates of clinic visits for AD and itch for adults aged 65 years and older compared with younger adults.
These results also indicate that the skin of older adults may be more vulnerable to air pollution, considering the rapid outcomes following short-term exposure to air pollution, as age-related molecular processes affect skin barrier function.
The researchers additionally recommended that health care systems increase access to medical professionals and other resources during wildfires to address exacerbations in AD and itch, along with clinical counseling and public health education, especially as wildfires increase in frequency and intensity.