Probiotics applied topically could promote a positive bacterial balance in the skin – similar to how oral probiotics increase diversity of flora in the gut – and may improve skin conditions, such as acne, say authors of a recent review published in Experimental Dermatology.1
Few studies have investigated the potential benefits of probiotics in acne management, but what data exist suggest they could be useful for acne as well as other inflammatory skin diseases, write authors Rebecca Knackstedt, M.D., of the Department of Plastic Surgery, Cleveland Clinic, and Thomas Knackstedt, M.D., of the Department of Dermatology, MetroHealth, Cleveland.1
The intestinal microbiome is known to have an impact on gut health, as well as wider systemic inflammation and disease. Some large meta-analyses have found that probiotics may be able to decrease the incidence of infections and need for antibiotics while improving wound healing, markers of inflammation and cholesterol levels. Oral probiotics have also demonstrated efficacy in treating other skin conditions such as atopic dermatitis and rosacea.
The skin microflora plays a similarly crucial role in regulating inflammation and the immune response. Dysregulation of both the innate and adaptive immune systems has been implicated in the pathogenesis of acne. Activation of toll‐like receptors and CD14 by Cutibacterium enables upregulation of inflammatory cytokines, such as TNF‐α, IL‐1B and IL‐8, which allows for the development of acne lesions, and can also trigger the adaptive immune system through Th1 cells and the humoral immunity.
Cutibacterium, the pathogen implicated in acne, is a commensal organism in healthy patients, so its presence alone is not responsible for the condition. Two strains – ribotype 4 and ribotype 5 – have been shown to only be present in patients with acne and may play a role in pathogenesis by an unclear mechanism.2
1. Knackstedt R, Knackstedt T, Gatherwright J. The role of topical probiotics on skin conditions: A systematic review of animal and human studies and implications for future therapies. Exp Dermatol. 2019;
2. Fitz-gibbon S, Tomida S, Chiu BH, et al. Propionibacterium acnes strain populations in the human skin microbiome associated with acne. J Invest Dermatol. 2013;133(9):2152-60.
3. Baquerizo nole KL, Yim E, Keri JE. Probiotics and prebiotics in dermatology. J Am Acad Dermatol. 2014;71(4):814-21.