The complex relationship between maternal smoking and atopic dermatitis in children

In this issue of the JEADV, L. Chao et al. perform a meta-analysis of studies examining the effect of smoking during pregnancy on the risk of atopic dermatitis in offspring.¹ While it is well-established that smoking during pregnancy adversely affects foetal development, particularly in terms of birth weight and overall growth, the impact on atopic dermatitis remains less understood. A recent study from Japan found that maternal smoking during pregnancy increases the risk of asthma in offspring, even after adjusting for pre- and postnatal covariates.²

Using PRISMA criteria, the authors identified 15 studies and found that active smoking does not increase the risk of atopic dermatitis, whereas passive smoking does.¹ This finding is consistent with a 2016 study that also found no increased risk associated with active smoking during pregnancy.³ The distinction between the effects of active and passive smoking is intriguing, as one might expect a dose-dependent response to tobacco smoke, with stronger associations for active smoking.

It is well-known that active tobacco smoking affects the immune system⁴ and has direct effects on the skin barrier and epidermal keratinocytes.⁵ However, the exact impact of these changes, particularly in the context of passive smoking, is still unclear and warrants further research.

Interestingly, L. Chao et al. note a trend suggesting that maternal smoking may have a protective effect against atopic dermatitis. This could be due to confounding factors, such as a lower genetic predisposition to atopic diseases in children of mothers who smoke. Additionally, there may be biases, such as non-smoking mothers being more sensitive to passive smoke exposure and over-reporting atopic dermatitis symptoms in their children.¹

The study by L. Chao et al. consolidates the current epidemiological evidence and discusses it in light of our understanding of the pathogenesis of atopic dermatitis and the biological effects of tobacco smoke. While there is substantial evidence of the harmful effects of smoking on foetal development, the results of this study raise important questions about how maternal immune responses and skin barrier functions influence the risks to the foetus. Further research is needed to clarify these complex interactions.

No conflicts of interest for this study.