Heat and Air Pollution Tied to Hidradenitis Suppurativa Risk

A research letter published May 8, 2026 in JAMA Dermatology has found that extreme heat exposure, air pollution, obesity, and Black race independently predict the development of hidradenitis suppurativa, a chronic inflammatory skin disease that has long resisted clean explanation. The University of California, San Francisco team, led by Aileen Y. Chang, used spatial epidemiological methods to map disease distribution across adults in the Boston metropolitan area. The analysis concluded that environmental exposure belongs in the same conversation as genetics and metabolic health when clinicians assess who is at risk for HS. ## Why Hidradenitis Suppurativa Has Been Hard to Pin Down Hidradenitis suppurativa is an inflammatory disorder of the apocrine-gland-bearing areas of skin, most often the underarms, groin, buttocks, and inframammary fold. It produces deep, painful nodules, abscesses, draining sinus tracts, and dense scarring. Patients typically wait between seven and ten years for an accurate diagnosis, often cycling through misdiagnoses of recurrent boils, ingrown hairs, or treatment-resistant acne. The disease has been studied extensively, but population-level risk factors have been hard to disentangle. Smoking and obesity emerged as consistent associations decades ago. Genetic variants in the gamma-secretase complex appear in a minority of familial cases. What has remained unclear is how the lived environment, including air quality and heat exposure, interacts with the immune dysregulation that drives flares. The JAMA Dermatology letter is among the first to formally implicate the exposome. ## How Significant Is the Environmental Signal in This Study? The study found that extreme heat exposure and air pollution were independent predictors of hidradenitis suppurativa even after adjusting for obesity and demographic variables. Black race remained an independent predictor as well, consistent with prior epidemiologic data showing disease prevalence more than threefold higher in Black individuals than in White individuals across US cohorts. The signal is large enough to warrant inclusion of environmental exposure in dermatologic risk modeling. The methodology matters. Spatial epidemiology lets investigators detect geographic clustering and correlate it with location-specific exposures, rather than relying on patient-reported recall. By layering environmental data, including pollutant concentrations and heat index measurements, on top of patient address records, the team isolated the contribution of place from individual factors like body mass index and smoking status. This approach has reshaped how dermatologists think about atopic dermatitis, where ozone, particulate matter, and traffic-related air pollution are now recognized as flare triggers in pediatric and adult populations. For clinicians, the practical implication is that asking about environmental exposure may belong in HS history-taking. For patients, it adds a class of factors that can be partially modified through air filtration, cooling strategies, and weight management, in addition to standard pharmacologic care. ## What Comes Next for Hidradenitis Suppurativa Research The next round of work will need to test these associations prospectively and identify the biological pathways that link heat and air pollution to follicular inflammation. Particulate matter is known to activate the aryl hydrocarbon receptor and disrupt epidermal barrier function, both mechanisms with plausible relevance to HS pathophysiology. Whether interventions like residential air filtration or heat-mitigation strategies can reduce flare frequency is an open question that the JAMA Dermatology authors flag as a priority. Therapeutic options for HS are also expanding rapidly. Adalimumab and secukinumab are now FDA-approved, and pipeline agents including povorcitinib and sonelokimab have shown activity in late-stage trials. Pairing these biologic advances with environmental risk reduction could shift HS care from purely reactive to genuinely preventive over the next decade. Readers tracking the broader picture can review our coverage of the skin microbiome and barrier function for related context on how environmental exposures influence inflammatory skin disease.