Małgorzata Mazur

The physiological acidity of the skin microenvironment constitutes a paramount component of passive innate defense against pathogenic colonization and subsequent dysbiosis. The objective of this review is to critically evaluate the sequelae of chronic epidermal barrier exposure to chemical exfoliants and to elucidate the impact of hydroxy acids on microbiota stability. An analysis of recent literature delineates fundamental discrepancies in their antimicrobial mechanisms, inflammatory modulation, and induction of stratum corneum desquamation. Conventional exfoliants, notably glycolic and salicylic acids, exhibit the capacity for passive diffusion into bacterial cells, where they undergo dissociation, precipitating destructive cytoplasmic acidification; furthermore, salicylic acid specifically downregulates crucial transcription factors. While these mechanisms facilitate the efficacious eradication of pathogenic organisms, they concurrently jeopardize commensal populations, which may paradoxically pave the way for secondary dysbiosis and opportunistic colonization. Next-generation acids, such as lactobionic acid, emerge as a highly promising, albeit insufficiently investigated, alternative. They exhibit the capacity to compromise bacterial cell walls and intercalate with microbial DNA. Future paradigms regarding the utilization of hydroxy acids in clinical dermatology must extend beyond traditional macroscopic endpoints to encompass the preservation of microbiome diversity and stability, thereby precluding chronic impairment of the associated protective barrier.

Bacteria inhabiting the digestive tract are responsible for our health. The microbiome is essential for the development of the immune system and homeostasis of the body. Maintaining homeostasis is very important, but also extremely complicated. The gut microbiome is related to the skin microbiome. It can therefore be assumed that changes in the microbes inhabiting the skin are greatly influenced by the bacteria living in the intestines. Changes in the composition and function of microbes (dysbiosis in the skin and intestines) have recently been linked to changes in the immune response and the development of skin diseases, including atopic dermatitis (AD). This review was compiled by collaborating Dermatologists specializing in atopic dermatitis and psoriasis. A comprehensive review of the current literature was performed using PubMed and limited to relevant case reports and original papers on the skin microbiome in atopic dermatitis. The inclusion criterion was that the paper was published in a peer-reviewed journal in the last 10 years (2012–2022). No limitations on the language of the publication or the type of study were made. It has been shown that any rapid changes in the composition of the microflora may be associated with the appearance of clinical signs and symptoms of the disease. Various studies have proven that the microbiome of many systems (including the intestines) may have a significant impact on the development of the inflammatory process within the skin in the course of AD. It has been shown that an early interaction between the microbiome and immune system may result in a noticeable delay in the onset of atopic diseases. It seems to be of high importance for physicians to understand the role of the microbiome in AD, not only from the pathophysiological standpoint but also in terms of the complex treatment that is required. Perhaps young children diagnosed with AD present specific characteristics of the intestinal microflora. This might be related to the early introduction of antibiotics and dietary manipulations in breastfeeding mothers in the early childhood of AD patients. It is most likely related to the abuse of antibiotics from the first days of life.