From Gut Dysbiosis to Skin Inflammation in Atopic Dermatitis - Probiotics and the Gut–Skin Axis - Clinical Outcomes and Microbiome Implications

Sep 30, 2026

Atopic dermatitis (AD) is a chronic inflammatory skin disease where barrier impairment, immune dysregulation, and gut–skin dysbiosis converge, increasing interest in probiotics as adjuncts that modulate microbiota. A narrative review summarized peer-reviewed evidence from PubMed, Scopus, and Google Scholar (1 Jan 2018–31 Oct 2025). Included studies covered RCTs, observational research, and mechanistic/conceptual reviews. Most pediatric multistrain, Lactobacillus-dominant probiotic regimens showed modest improvements in AD severity, pruritus, and some barrier- and inflammation-related biomarkers, while cutaneous microbiome “restoration” was uncommon. Effects with single strains were inconsistent, and findings in adolescents and adults were heterogeneous, limiting firm recommendations despite plausible gut–skin mechanisms.

LanguageEnglish

CategoryHealthcare

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Abstract

1. Introduction and Background

1.1. The Skin and Gut Microbiome

Review From Gut Dysbiosis to Skin Inflammation in Atopic Dermatitis: Probiotics and the Gut–Skin Axis—Clinical Outcomes and Microbiome Implications Adina Elena Micu 1,2, Ioana Adriana Popescu 1,2, *, Ioana Alina Halip 1,2, Mădălina Mocanu 1,2, Dan Vâă 1,2, Andreea Luana Hulubencu 2, Dragos, Florin Gheucă-Solovăstru 1 and Laura Gheucă-Solovăstru 1,2 Academic Editor: Terenzio Cosio Received: 17 November 2025 Revised: 19 December 2025 Accepted: 23 December 2025 Published: 29 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Department of Dermatology,“Grigore T. Popa” University of Medicine and Pharmacy, 700115 Ias, i, Romania; [adinaursache096@gmail.com](adinaursache096@gmail.com) (A.E.M.); [alinaioanahalip@gmail.com](alinaioanahalip@gmail.com) (I.A.H.); [drmadalinamocanu@yahoo.com](drmadalinamocanu@yahoo.com) (M.M.); [danvata@gmail.com](danvata@gmail.com) (D.V.); [lsolovastru13@yahoo.com](lsolovastru13@yahoo.com) (L.G.-S.) 2 Department of Dermatology,“St. Spiridon” Emergency County Clinical Hospital, 700111 Ias, i, Romania; [hulubencuandreea@gmail.com](hulubencuandreea@gmail.com) * Correspondence: [oana.manolache@yahoo.com](oana.manolache@yahoo.com); Tel.: +40-741-104-502 Abstract Atopic dermatitis (AD) is a chronic inflammatory skin disease in which barrier impairment, immune dysregulation, and gut–skin dysbiosis intersect, prompting growing interest in probiotics as microbiota-modulating adjuncts. We conducted a narrative review of peerreviewed articles indexed in PubMed, Scopus, and Google Scholar, restricted to publications from 1 January 2018 to 31 October 2025 (searches last run in December 2025) . Eligible evidence included randomized controlled trials (RCTs), observational studies, and mechanistic or conceptual reviews addressing microbiome alterations and microbiota-modulating interventions in AD. Most pediatric RCTs using multistrain, Lactobacillus-dominant formulations (often combined with Bifidobacterium) reported modest improvements in AD severity and pruritus and in selected barrier-and inflammation-related biomarkers. However, direct cutaneous microbiome “restoration” outcomes were reported in a minority of studies, and most clinical evidence relies on clinical endpoints and gut–skin axis plausibility rather than longitudinal skin microbiome readouts. Single-strain regimens showed inconsistent effects, and evidence in adolescents and adults remained heterogeneous. Mechanistically, probiotics may enhance short-chain fatty acid (SCFA) signaling, dampen toll-like receptor 2/4 (TLR2/4)-nuclear factor kappa B (NF-κB) activation, and promote interleukin-10 (IL-10)-and transforming growth factor-β (TGF-β)-driven tolerance. Probiotics are a biologically plausible adjunct targeting the gut–skin axis in AD and are generally well tolerated; however, heterogeneity across trials, limited follow-up, inconsistent adverse-event reporting, and scarce skin microbiome endpoints preclude firm clinical recommendations. Keywords: probiotics; gut–skin axis; dysbiosis; atopic dermatitis; microbiome 1. Introduction and Background 1.1. The Skin and Gut Microbiome The skin and gut are both active, complex immunological and neuroendocrine organs that are in constant contact with the external environment and host diverse microbial communities. Proper functioning of these systems is essential for maintaining homeostasis and supporting survival. The skin, as the body’s largest organ, acts as a protective barrier against injury and microbial invasion, while the gut harbors trillions of microorganisms, functioning as a “virtual organ” closely linked to the host’s health and longevity. The gut microbiome exerts both beneficial and detrimental effects on the physiology and homeostasis of gut and skin tissues [1] . Traditionally, the skin ha

FAQs

What is the rationale for using probiotics in atopic dermatitis?

Probiotics are explored as a biologically plausible adjunct targeting the gut–skin axis, potentially improving AD through microbiota modulation and immune regulation.

What types of studies were included in this review?

The review covered randomized controlled trials, observational studies, and mechanistic or conceptual reviews addressing microbiome alterations and microbiota-modulating interventions in AD.

Why are firm clinical recommendations limited?

Evidence is restricted by heterogeneity across trials, limited follow-up, inconsistent adverse-event reporting, and a scarcity of longitudinal skin microbiome endpoints.

Sep 30, 2026

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