Current interventions to tackle Staphylococcus aureus in patients with atopic eczema have little impact on symptoms, based on data from a Cochrane Review of 41 studies.
Eczema remains a huge disease burden worldwide, and colonization with S aureus in eczema patients is common, but no standard intervention exists to relieve symptoms, writes Nandini Banerjee, MD, of Addenbrooke’s Hospital, Cambridge, United Kingdom. “While antibiotic treatment of clinically obvious infections such as cellulitis is beneficial, it is not clear whether antibiotic treatment of eczema influences eczema severity,” Banerjee notes.
The 41 studies included 1753 participants and 10 treatment categories. Most of the studies were conducted in secondary care centers in Western Europe, North America, and the Far East. A total of 12 studies included children, four included only adults, 19 included children and adults, and in six studies, the participant age range was unclear. Among the studies with reported ages, the mean age ranged from 1.1 to 34.6 years. Eczema severity ranged from mild to severe, and treatment durations ranged from 10 minutes to 3 months.
The review presented comparisons of topical steroid/antibiotic combinations, oral antibiotics, and bleach baths. In 14 studies that compared topical steroid/antibiotic combinations to topical steroids alone, patients showed slightly greater global improvement in symptoms with the combination, but the impact on quality of life was not significantly different. Severe adverse events, including flare of dermatitis, worsening of eczema, and folliculitis, were reported by the patients who received the combination and the topical steroid–only patients. One study reported similar rates of antibiotic resistance in children treated with steroid only and with an antibiotic/steroid combination at 3 months’ follow-up.
In four studies of oral antibiotics, “Oral antibiotics may make no difference in terms of good or excellent global improvement in infants and children at 14 to 28 days follow-up compared to placebo,” according to the review. The reviewers note that there was likely little or no difference in quality of life for infants and children given oral antibiotics, although they note the low quality of evidence on this topic.
Five studies evaluated the impact of bleach baths on eczema patients with and without S aureus infections. These studies showed no difference in global improvement measures compared with placebo and little or no difference in quality of life. Also, patients who underwent bleach baths compared with placebo patients reported similar adverse events of burning/stinging or dry skin at 2 months’ follow-up.
“Low-quality evidence, due to risk of bias, imprecise effect estimates, and heterogeneity, made pooling of results difficult,” Banerjee writes. “Topical steroid/antibiotic combinations may be associated with possible small improvements in good or excellent signs/symptoms compared with topical steroid alone. High-quality trials evaluating efficacy, QOL and antibiotic resistance are required,” she concludes.
In a commentary section after the review, Banerjee and colleagues note that the United Kingdom’s NICE guidelines for managing atopic eczema in children younger than 12 years of age, published in March 2021, include evidence from the current updated Cochrane Review. The NICE guidelines also emphasize that “in people who are not systemically unwell, clinicians should not routinely offer either a topical or oral antibiotic for secondary bacterial infection of eczema,” the Cochrane authors say. They add in their commentary that the use of antibiotics in cases of nonsevere infections can worsen eczema. Also, “the risk of antimicrobial resistance is high with topical antibiotics, and therefore extended doses of the same antibiotics should be avoided to prevent resistance,” they say. However, the authors acknowledge a role for antibiotics in certain situations. “In patients with systemic signs of infection such as cellulitis, systemic antibiotics have an important role in helping clear infection,” they note.
Reasons for Varying Disease Severity Elude Research
The current study is important because of the abundance of preclinical and clinical data that implicate S aureus in atopic dermatitis pathogenesis, said Brian Kim, MD, of the Icahn School of Medicine at Mount Sinai, New York, in an interview with Medscape Medical News.
Kim said that he was surprised by some of the study findings but not others. “On the one hand, I thought there would be data supporting antimicrobial therapy, albeit not strong support,” he said. “However, AD is a very complex disease, and understanding what a disease modifier does to it is hard to capture across studies of various different designs,” he said.
“The data supporting antimicrobial therapy for S aureus in AD is not as clear as our clinical impressions may indicate,” said Kim. “We need to understand the relationship better, perhaps in particular subsets of patients,” he emphasized. In addition, “We need a better understanding of why some people are colonized with S aureus, yet with little effect on AD itself, while others experience severe exacerbation of disease,” said Kim. Therefore, a key research question for future studies is whether the exacerbation is caused by the particular strain of the bug, the host susceptibility, or both, he said.
The review received no outside funding. Banerjee and Kim have disclosed had no relevant financial relationships.
Clin Exp Allergy. Published online January 14, 2022. Full text