Probiotics for treating eczema

Robert John Boyle, Fiona J Bath‐Hextall, Jo Leonardi‐Bee, Dedee F Murrell, Mimi LK Tang

Probiotics have been proposed as an effective treatment for eczema, and recently a number of clinical trials have been undertaken. To assess the effects of probiotics for the treatment of eczema We searched the Cochrane Skin Group Specialised Register (to April 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2,2008) MEDLINE (from 2003 to April 2008), EMBASE (from 2005 to April 2008), PsycINFO, AMED and LILACS (from inception to April 2008) and ISI Web of Science (to December 2006) and reference lists of articles. We also searched registries of ongoing clinical trials, conference proceedings and searched for adverse events. Randomised controlled trials of live orally ingested microorganisms for the treatment of eczema. Two authors independently applied eligibility criteria, assessed the quality of trials and extracted data. We contacted study authors for more information where necessary. We recorded adverse events from the included studies, and from the separate adverse events search. Twelve randomised controlled trials involving 781 participants met the inclusion criteria. All trial participants were children. There was no significant difference in participant or parent-rated symptom scores in favour of probiotic treatment (5 trials, 313 participants). Symptom severity on a scale from 0 to 20 was 0.90 points lower after probiotic treatment than after placebo (95%CI -1.04, 2.84; p = 0.36).There was also no significant difference in participant or parent-rated overall eczema severity in favour of probiotic treatment (3 trials, 150 participants). There was no significant difference in investigator rated eczema severity between probiotic and placebo treatments (7 trials, 588 participants). On a scale from 0 to 102 investigator rated eczema severity was 2.46 points lower after probiotic treatment than after placebo treatment (95%CI -2.53, 7.45 p = 0.33). Significant heterogeneity was noted between the results of individual studies, which may be explained by the use of different probiotic strains. Subgroup analysis by age of participant, severity of eczema, presence of atopy or presence of food allergy did not identify a population with different treatment outcomes to the population as a whole. The adverse events search identified some case reports of infections and bowel ischaemia caused by probiotics. The evidence suggests that probiotics are not an effective treatment for eczema, and probiotic treatment carries a small risk of adverse events.