Does Staphylococcus aureus colonization make my atopic dermatitis worse?
Staphylococcus aureus (S. aureus) is a bacterium that commonly lives on the skin of people with atopic dermatitis (AD). Research shows that higher levels of S. aureus on the skin are associated with more severe AD symptoms. This does not necessarily mean S. aureus causes the worsening, but it is a strong clue that it plays a role in flare-ups.
What the research says
A 2025 systematic review and meta-analysis of 7 randomized controlled trials involving 929 participants found a moderate positive correlation between S. aureus colonization and AD severity (r = 0.42, 95% CI: 0.31–0.52) 2. This means that as S. aureus levels increase, AD severity tends to increase as well. However, the authors caution that this correlation should not be interpreted as proof of a direct causal relationship 2.
Other studies provide context for this link. A 2017 study found that healthy skin often has beneficial bacteria (coagulase-negative Staphylococcus) that produce antimicrobial peptides killing S. aureus, but these protective bacteria are less common on the skin of people with AD 9. Reintroducing these beneficial bacteria to AD patients reduced S. aureus colonization 9. A 2020 review confirms that S. aureus abundance on AD skin is linked to reduced bacterial diversity and increased disease severity 10. Additionally, a 2017 study using metagenomic sequencing showed that during AD flares, S. aureus becomes more dominant, especially in patients with more severe disease, and that different S. aureus strains can cause different levels of skin inflammation in mice 11.
While these findings strongly suggest S. aureus worsens AD, the evidence is not yet conclusive about cause and effect. The moderate correlation and the success of treatments that reduce S. aureus (like certain antimicrobial strains) point to an important role, but more research is needed to fully understand the relationship.
What to ask your doctor
- Could testing for S. aureus on my skin help guide my treatment?
- Are there treatments that specifically target S. aureus to improve my AD?
- Would using topical antibiotics or antimicrobial washes be appropriate for me?
- How can I tell if a flare is related to S. aureus versus other triggers?
- Are there any probiotics or bacterial therapies that might help reduce S. aureus on my skin?
This question is drawn from common patient questions about Dermatology and answered using cited medical research. We do not provide individualized advice.