Wildfire Air Pollution Associated with Increase in Psoriasis Flares

Air pollution from wildfires was linked to significant increase in clinical visits for psoriasis among adults starting 5 weeks after the fire and peaking at 8-9 weeks, according to the results of a study published in Jama Network Open.

“In addition, we collected weekly online search interest data (ie, search value index [SVI]) from Google Trends for the term psoriasis in San Francisco in 2018,” the authors said. “The mean weekly SVI for psoriasis from October 4, 2018, to January 30, 2019, showed an increase in search volume also starting 5 weeks after the fire and peaking at week 8.”

To characterize air pollution in San Francisco, California, investigators used fire status, concentration of PM2.5 measured at ground level, and smoke plume density, ranging from 0 to 3, with 0 indicating none, 1 indicating light, 2 indicating medium, and 3 indicating heavy, based on satellite imaging.

They used data collected for outpatient dermatology visits for psoriasis at an academic medical center in San Francisco from October 2018 to February 2019, October 2015 to February 2016, and October 2016 to February 2017. The total 986 clinic visits included 914 adults and 72 children with psoriasis.

For adults, the earliest significant increase of clinic visits by fire status for psoriasis occurred at the 5-week lag (RR, 1.32 [95% CI, 1.02-1.70]) and peaked at the 8-week lag (RR, 1.45 [95% CI, 1.13-1.86]) and 9-week lag (RR, 1.45 [95% CI, 1.12-1.87]). There were no significant results for children with psoriasis.

The authors acknowledged the limitations of the study that the focus of their study was only 1 wildfire, which affected San Francisco from a distance, and that the minority population in the study was also underrepresented, so the results may also be unrepresentative of the subgroup population.

—Priyam Vora

Reference:
Fadadu RP, Green M, Grimes B, Jewell NP, Seth D, Vargo J and Wei ML. JAMA Netw Open. 2023;6(1):e2251553. doi:10.1001/jamanetworkopen.2022.51553