Background Probiotic, prebiotic, and synbiotic supplementation is becoming more prevalent nowadays. Clinical studies have demonstrated some of the medical benefits of probiotics, prebiotics, and synbiotics within dermatology but an evidence-based review of their effects in adults is needed.Objective The aim of this study was to identify evidence for the use of supplementation with probiotics, prebiotics, or synbiotics for the prevention and treatment of dermatological diseases in adults.Data sources We conducted a search of the Ovid MEDLINE, Cochrane Central Register of Controlled trials and EMBASE electronic databases from 1 January 1946 to 11 January 2017.Study selection Trials examining supplementation in the treatment of dermatological diseases using oral or topical probiotics, synbiotics, and prebiotics in adults over the age of 18 years were selected.Data extraction Of 315 articles, 12 met the inclusion criteria.Data synthesis Nutritional supplementation with probiotics and prebiotics was shown to improve atopic dermatitis (AD) symptomatology, quality of life, or clinical severity in six of nine studies. One study in psoriasis was shown to improve inflammatory markers, and one study suggested that probiotics could be used as adjunctive therapy in the treatment of acne.Conclusion Preliminary studies are optimistic for the use of some strains of probiotics for symptomatic and clinical improvement in AD, and as adjunctive treatment with antibiotics for acne. Further research is necessary to better assess how probiotics and prebiotics may be used within dermatology.