Abstract
BACKGROUND: Inherited ichthyoses (iI) are a heterogeneous group of keratinization disorders, whose microbiome composition and the role of dysbiosis remain largely unexplored. OBJECTIVES: Characterization of the skin microbiome profile in iI and exploration of the significance of dysbiosis based on the literature. METHODS: A systematic search was performed across MEDLINE, Embase, Cochrane Library, Web of Science, and Scopus on 23 September 2024. Studies with culture-based and molecular diagnostic methods were included. RESULTS: 1923 records were retrieved, and 13 met our inclusion criteria. The studies identified focused on non-syndromic and syndromic ichthyosis genotypes. Significant dysbiosis was observed in iI subtypes, with altered alpha and beta diversity. Subtype-specific alterations included elevated levels of pathogenic bacteria, such as Staphylococcus aureus, while the relative abundances of commensal microbes, including Cutibacterium acnes and Malassezia globosa, were significantly reduced in all ichthyoses examined. These changes were closely related to clinical severity, transepidermal water loss, and elevated proinflammatory cytokines. LIMITATIONS: The heterogeneity of studies is a limitation. CONCLUSIONS: These findings emphasize the distinct microbiome profiles of different iI subtypes, marked by an imbalance, enrichment of pathogenic microorganisms, and a reduction in protective microbes. This dysbiosis is linked to disease severity and inflammation.