RESEARCH LETTER The Prevalence of Secondhand Smoke Exposure in Hidradenitis Suppurativa: A Cross-Sectional Survey Study

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Hidradenitis Suppurativa (HS) is a chronic inflammatory disease of the skin associated with several risk factors, including genetic susceptibility, obesity, and firsthand smoking. 1,2 Firsthand smoke is the smoke inhaled directly by the person using tobacco products, including cigarettes, cigars, pipes, hookahs, and vaping devices. 3 While firsthand smoking is highly prevalent in patients with HS 4 , secondhand smoke, defined as the inhalation of smoke from burning a tobacco product or smoke that is exhaled by smokers, 5 and its relationship to HS has not been assessed. This study aims to determine the prevalence of secondhand smoke exposure among a sample of HS patients. This is a cross-sectional study, and data collection occurred from December 1, 2021, to May 31, 2022. A survey was distributed to patients at the University of Alabama at Birmingham general and pediatric dermatology clinics who were diagnosed with ABSTRACT Introduction: Hidradenitis Suppurativa (HS) is a chronic inflammatory disease of the skin highly associated with firsthand smoking. Secondhand smoke, defined as the inhalation of smoke from burning a tobacco product or smoke that is exhaled by smokers, and its relationship to HS has not been assessed. This study aims to determine the prevalence of secondhand smoke exposure in the HS population. Methods: In this cross-sectional study (N=136), surveys were both administered in a dermatology clinic and emailed to patients with HS, verruca vulgaris (VV), and atopic dermatitis (AD). Control groups were selected based on secondhand smoke associations: AD has a known association, whereas VV does not. Results: The survey response rate was 67.3% (N=136). We found that more than half of HS patients (58.73%) were exposed to secondhand smoke within the last 12 months, whereas 38.30% and 30.77% in the AD and VV groups were exposed, respectively (p=0.0209). However, our data did not identify a significant correlation between secondhand smoke and HS disease severity. Conclusion: Our study is the first to assess the prevalence of secondhand smoke exposure in the HS population. Although we observed a statistically significant increased prevalence of secondhand smoke in HS patients, we could not establish how it may affect severity of disease. Our study highlights an area for further investigation evaluating the relationship between passive tobacco exposure and inflammatory skin disease.
HS, atopic dermatitis (AD), or verruca vulgaris (VV) by a dermatologist and who were aged 14+. Additionally, surveys were also emailed to participants based on retrospective diagnosis. Control groups were selected based on secondhand smoke associations: AD has a known association, whereas VV does not. In terms of definitions, HS severity (mild, moderate, or severe) was self-reported by participants based on descriptions provided in the survey, and active secondhand smoke exposure was defined as the inhalation of smoke from a tobacco product exhaled by another person within the last 12 months. Statistical analyses were performed using JMP Pro 16 at α=0.05 significance level.
The survey response rate was 67.3% (N=136). Most HS patients (53.97%) reported having moderate HS defined as having 'recurrent abscesses and nodules with tracts or scarring' ( Table 1). There was no significant difference between smoking status (i.e., never smoker, past smoker) among the three skin condition groups (p=0.1813). Additionally, 51.5% of the total sample reported one or more household members being smokers during their childhood, with no significant differences between skin condition groups (p=0.2448).
More HS patients reported experiencing active secondhand smoke exposure (defined as tobacco exposure within the last 12 months) than those with AD and VV (p=0.0209, Table 1). Although HS patients more likely reported secondhand smoke exposure than other groups, there was no difference in self-reported HS disease severity among those with secondhand smoke exposure and those without (p=0.2419).
In summary, our study found that a majority of HS patients (58.7%) were exposed to secondhand smoke. Compared to patients with AD and VV, HS patients had significantly higher rates of secondhand smoke exposure; however, there was no significant correlation between secondhand smoke and HS disease severity.
Research illustrates that tobacco smoke promotes proinflammatory cytokines and various inflammatory pathways in HS lesions that contribute to disease progression. 1 Based on the knowledge of how smoking tobacco affects chronic inflammatory skin diseases such as AD and HS, it is possible that significant secondhand smoke exposure can act similarly. While data on the effects of passive smoke exposure on HS is currently limited, our results identify the increased prevalence of secondhand smoke in HS.
While smoking cessation can lead to improved outcomes 4 , more research is needed to evaluate whether complete smoke avoidance would be effective and reasonable for HS patients. This is an essential consideration in the pediatric population, who have little to no control over the smoke exposure they receive in the household.
This single-center study was limited by a small sample size and significant differences between groups which impacted the ability to compare and draw conclusions about secondhand smoke exposure. Additionally, several variables that may influence secondhand smoke prevalence, including race, socioeconomic factors, and age, 6 were not accounted for and may have confounded the results. According to the Centers for Disease Control and Prevention, secondhand smoke exposure is more