No Link Between Smoking and Eczema

Original Article: Atopic dermatitis and tobacco smoke exposure during childhood and adolescence

What are the key takeaways of this article?

This large, longitudinal study aimed to clarify whether tobacco smoke exposure (TSE)—either passive (secondhand) or active (teen smoking)—influences the activity or severity of atopic dermatitis (AD) in children and adolescents. Investigators analyzed data from the Avon Longitudinal Study of Parents and Children (ALSPAC), which followed over 10,000 participants from infancy through their late teens.

The researchers measured passive TSE based on maternal reports of secondhand smoke exposure at ages 2, 3, 4, 5, 6, and 8 years, and active TSE based on adolescents’ self-reported smoking habits at ages 10, 13, 15, and 17. To validate these reports objectively, they examined serum cotinine levels—a reliable biomarker of nicotine metabolism—at ages 6, 15, and 17. AD activity and severity were assessed through repeated questionnaires, distinguishing between “no problem/mild” and “moderate/severe” disease.

After adjusting for potential confounders, including measures of socioeconomic status (such as parental education, housing conditions, and financial difficulties), the analyses showed no statistically significant link between passive TSE and AD across childhood. Likewise, active smoking in adolescence was not associated with an increased risk of AD onset, severity, or flare-ups. Although an unadjusted inverse relationship initially emerged—suggesting AD might be less common among exposed individuals—this relationship disappeared or became inconsistent once critical confounders were controlled. Additional tests using serum nicotine confirmed that neither passive nor active TSE significantly impacted AD risk or severity.

An important secondary objective was to explore gene–environment interactions involving the filaggrin (FLG) gene, known to affect skin barrier function. However, there was no evidence that FLG null mutations modified the relationship between TSE and AD, though relatively few participants carried these mutations.

Overall, these findings counter previous reports suggesting a strong association between tobacco exposure and AD. The results emphasize the importance of properly adjusting for socioeconomic factors and demonstrate that childhood and adolescent tobacco smoke exposure does not appear to be a direct driver of AD. Despite these neutral results regarding AD, the authors underscore the well-established health risks of tobacco exposure in pediatric populations, reinforcing the need for continued public health efforts to reduce secondhand and active smoking for other health considerations.

Publication Date: February 27, 2025

Reference: Al-Alusi NA, Ramirez FD, Chan LN, et al. Atopic dermatitis and tobacco smoke exposure during childhood and adolescence. J Allergy Clin Immunol Glob. 2024;4(1):100345. doi:10.1016/j.jacig.2024.100345

Summary By: Parsa Abdi