Brain cancer is one of the most aggressive cancer types owing to poor treatment effects. Epidemiological studies have demonstrated that allergies may increase the disease risk. Therefore, this study evaluated the association between eczema and the risk of various brain cancers.

We systematically searched the PubMed and Embase databases from their inception until June 23, 2022. Two reviewers independently reviewed and screened the articles, extracted data, assessed the study quality, and pooled the results. Stata software was used to generate pooled odds ratios and 95% confidence intervals (CIs).

We included 20 studies comprising 5,117,222 patients that investigated the relationship between eczema and brain cancer. Eczema was significantly inversely associated with the risk of brain cancer (odds ratio [OR], 0.82; 95% CI, 0.77–0.87), glioma (OR, 0.53; 95% CI, 0.14–2.02), meningioma (OR, 0.74; 95% CI, 0.66–0.84), and acoustic neuroma (OR, 0.60; 95% CI, 0.41–0.88). Interesting, The strong correlation between eczema and the reduced risk of brain cancer was observed in people over 16 years old (OR, 0.79; 95% CI, 0.71–0.88), but not in those under 16 years old (OR, 0.94; 95% CI, 0.79–1.11). In addition, subgroup analyses found that eczema significantly decreased the glioma risk in Europeans (OR, 0.73; 95% CI, 0.65–0.82) but not Australians (OR, 0.53; 95% CI, 0.14–2.02) or Americans (OR, 1.01; 95% CI, 0.69–1.46).

Eczema may be considered as a potential protective factor of brain cancer in population aged over 16 years. However, this relationship requires verification using large-scale clinical data.