Antimicrobial and Steroid Combination Therapy Restores Skin’s Bacterial Microbiome in Patients with AD

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A new study combined topical antimicrobials with corticosteroids for atopic dermatitis (AD) to measure how the treatment improves the skin microbiome and barrier.¹ Researchers compared this to corticosteroids on their own and found the combination therapy to be more effective.

Skin with AD lesions has more Staphylococcus and less Streptococcus, Corynebacterium, and Cutibacterium bacterium.² However, using antimicrobials can be controversial as it may lead to drug resistance, according to the study authors.

“The pathogenesis of AD has been linked to a sebum–microbial metabolite axis, which is influenced by disease activity and treatment outcomes,” the authors wrote.

The randomized controlled trial took place at Peking University First Hospital between August 2023 and July 2024. Forty patients with mild to moderate AD were randomly assigned to receive either an econazole/triamcinolone combination topical (Pevisone) or a triamcinolone acetonide acetate cream.

Participants had an Investigator’s Global Assessment (IGA) score of ≤ 3 and an Eczema Area and Severity Index (EASI) score of < 16 at baseline. All were directed to stop using other topical or systemic therapies for AD but were permitted to use nonmedicated topical emollients. Healthy controls (n = 48) were also included.

Lesional and non-lesional skin swabs were collected and analyzed at baseline, immediately after treatment, and 2 weeks post-treatment. Investigators also assessed disease severity, itch, transepidermal water loss (TEWL), and sebum using measurement tools like IGA, EASI, Scoring of Atopic Dermatitis (SCORAD), and the Peak Pruritus Numerical Rating Scale (PP-NRS).

Both treatment regimens were successful in improving AD severity and reducing itch. After 2 weeks, 88.2% of the combination group and 89.5% of the steroid group achieved clear or almost clear skin, according to the IGA scale. TEWL was also decreased and then maintained post-treatment in both lesional and non-lesional sites. At baseline, TEWL was slightly higher in AD patients than in the healthy controls (p < 0.01).

Moreover, the patients receiving the combination therapy had a greater increase in sebum levels than those who were only using the topical steroid. The combination therapy also restored the skin bacterial microbiome, which the steroid alone did not. 

The presence of Staphylococcus was significantly reduced while Cutibacterium was significantly increased after treatment (p < 0.05). This made the bacterial microbiome similar to that of controls. Cutibacterium in particular is known for improving the lipid barrier and could help to maintain skin homeostasis for those with AD.

There was also a change in fungal diversity, specifically an increase in Malassezia and a decrease in Candida, but this reverted back at 2 weeks post-treatment. These findings are particularly noteworthy, as certain Malassezia species have been proven to damage the skin barrier in AD.³

The study does have some limitations, including the small number of patients, which can impact the statistical analysis. Additionally, although the short follow-up period saw complete improvement in 86.5% of the patients, a longer follow-up would demonstrate even greater efficacy. This can be evaluated in future studies.

“Considering the critical role of microbiome dysbiosis in AD, further research is necessary to explore therapeutic approaches aimed at rebalancing the microbial community and evaluating their clinical outcomes,” the authors concluded.

References

1. Tingting L, Zhang P, Yang L, Li R, Wang R. The effects of topical antimicrobial-corticosteroid combination therapy in comparison to topical steroids alone on the skin microbiome of patients with atopic dermatitis. J Dermatolog Treat. 2025;36(1):2470379. doi:10.1080/09546634.2025.2470379

2. Edslev SM, Agner T, Andersen PS. Skin Microbiome in Atopic Dermatitis. Acta Derm Venereol. 2020;100(12):adv00164. Published 2020 Jun 9. doi:10.2340/00015555-3514

3. Tao R, Li R, Wang R. Dysbiosis of skin mycobiome in atopic dermatitis. Mycoses. 2022;65(3):285-293. doi:10.1111/myc.13402