Interventions to reduce Staphylococcus aureus in the management of atopic eczema

Background Staphylococcus aureus can cause secondary infection in atopic eczema, and it may promote inflammation in eczema that does not look infected. Many antimicrobial products exist for eczema, but it is unclear if they work or if they promote bacterial resistance. Objectives To assess the effects of interventions to reduce Staphylococcus aureus for treating infected or uninfected atopic eczema. Search strategy We searched the Cochrane Skin Group Specialised Register (March 2008), the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 1, 2008), MEDLINE (OVID) (from 2002 to March 2008), EMBASE (OVID) (from 2002 to March 2008), Ongoing trials registers (March 2008). References from trials and reviews were searched, pharmaceutical companies were contacted for unpublished trials. There were no language restrictions. Selection criteria Randomised controlled trials (RCTs) of people with atopic eczema who have been treated with a product intended to reduce S. aureus on the skin. Data collection and analysis Two people independently performed the study selection, data abstraction and quality assessment. Main results We included 21 studies (1018 participants) covering 7 treatment categories. Most studies were poorly reported and study differences limited pooling of results. Adverse effects were especially poorly reported, and only one study reported the emergence of resistant bacterial strains following oral antibiotics. Oral antibiotics were not associated with benefit in non-infected (2 trials, 66 participants) or infected eczema (1 trial, 33 participants). We did not find any benefit for antibacterial soaps (1 trial, 50 participants), or antibacterial bath additives (2 trials, 41 participants), or topical antibiotics/antiseptics (4 studies, 95 participants). Adding antibiotics to topical corticosteroids reduced numbers of Staphylococcus aureus in 4 trials (302 participants), but there was no evidence of any clinical benefit in 9 trials involving 677 participants: betamethasone plus neomycin vs clobetasol (MD 1.2; 95% CI 0.25, 2.15), prednicarbate plus antimicrobial vs prednicarbate (RR 0.64; 95% CI 0.25, 1.68), or betamethasone valerate plus gentamicin vs betamethasone (RR 0.31; 95% CI 0.07, 1.35). One trial (30 participants) showed no significant improvement in eczema for those using silver textiles (RR 2.67; 95% CI 0.98, 7.22), despite using 10 times the amount of topical steroids. Authors' conclusions We failed to find clear evidence of benefit for antimicrobial interventions for people with atopic eczema, despite their widespread use. This does not necessarily mean they do not work because the studies were small and poorly reported. Further large studies with long-term outcomes and clearly defined participants are urgently required.