Apple Cider Vinegar Soaks for Eczema: What the Study Shows

observational-study PMID: 34077434

Apple Cider Vinegar Soaks for Eczema: What the Study Shows

Quick Summary: A small study tested if daily apple cider vinegar soaks could change the bacteria on the skin of people with atopic dermatitis, a common type of eczema. Researchers found that soaking in diluted apple cider vinegar for two weeks did not shift the skin's bacterial balance or reduce harmful bacteria like Staphylococcus aureus compared to plain water soaks. This suggests apple cider vinegar may not help fix skin bacteria issues in eczema at this low strength.

What the Research Found

This pilot study looked at how apple cider vinegar affects the skin's bacterial community, called the microbiome, in people with atopic dermatitis. Eczema skin often has fewer types of good bacteria and more harmful ones like Staphylococcus aureus, which can make symptoms worse.

Key results in simple terms:
- No change in skin bacteria overall: After 14 days, the bacterial mix on eczema skin stayed the same whether treated with diluted apple cider vinegar or tap water.
- No drop in bad bacteria: Levels of Staphylococcus aureus didn't decrease on arms soaked in apple cider vinegar.
- Similar to healthy skin: By the end, the bacterial diversity in eczema patients' skin wasn't much different from healthy people's skin, but the vinegar didn't cause this—it happened with water too.

Apple cider vinegar is popular for its antibacterial properties, but this research shows it didn't make a noticeable difference in skin bacteria at the tested dose.

Study Details

Who was studied: 11 adults with mild-to-moderate atopic dermatitis (eczema) and 11 healthy adults without skin issues. Everyone was their own comparison, with one arm getting the treatment and the other acting as a control.
How long: 14 days of daily soaks, with skin samples taken before starting and after two weeks.
What they used: A weak solution of apple cider vinegar (0.5% acetic acid, the active part) versus plain tap water. Participants soaked one forearm in each for 10 minutes a day.

Scientists analyzed skin swabs using a lab technique called 16S sequencing to check bacteria types and variety. The study was randomized but not blinded, meaning participants knew which arm got the vinegar.

What This Means For You

If you have eczema, you might have heard apple cider vinegar soaks could soothe your skin or fight bacteria naturally. This study says that at this mild strength (like a very diluted mix), it won't change your skin's bacterial balance or cut down on Staph aureus, a common trigger for flare-ups.

Skip it as a main fix: Don't rely on apple cider vinegar soaks alone for eczema. Stick to proven treatments like moisturizers, steroid creams, or doctor-recommended routines to manage symptoms and prevent infections.
Try with caution: Some people use it for its mild acidity to balance skin pH, but this research didn't test that. Always dilute it well to avoid irritation, and talk to your doctor before trying—especially if your skin is sensitive.
Bigger picture: Eczema care is personal. Focus on gentle skincare and avoiding triggers while waiting for more research on stronger vinegar doses or longer use.

Study Limitations

This was a small, early-stage study, so results aren't the final word. Here's what to keep in mind:
- Small group: Only 22 people took part, so it might not apply to everyone with eczema.
- Short time frame: Two weeks may not show long-term effects; longer trials could reveal more.
- One strength only: They used a low 0.5% concentration—higher amounts might work differently but could irritate skin.
- No blindness: Participants knew about the treatments, which might influence how they felt or reported results.
- Missed other benefits: The study focused on bacteria, not itchiness, redness, or overall eczema severity, so vinegar might help in other ways not measured here.
- Single location: Done at one clinic, so findings might vary by person or place.

More research is needed to check different vinegar strengths and how they affect real eczema symptoms. For now, base your routine on evidence-based advice from healthcare pros.

Source: 2021 study from University of Virginia (UVA IRB-HSR #19906), published in PubMed.

Key Findings

The study found that daily topical application of dilute apple cider vinegar (0.5% acetic acid) did not significantly alter the skin bacterial microbiome composition, diversity, or Staphylococcus aureus abundance in individuals with atopic dermatitis (AD) compared to tap water soaks. No statistically significant differences were observed between AD patients and healthy controls after 14 days of treatment.

Study Design

This was a randomized, non-blinded, split-arm pilot study conducted at a single institution. The sample included 11 adults with mild-to-moderate AD and 11 healthy controls. Over 14 days, participants soaked one forearm in dilute ACV (0.5% acetic acid) and the other in tap water for 10 minutes daily. Skin bacterial samples were collected pre-treatment and post-treatment, analyzed via 16S rRNA sequencing for microbiome composition and diversity (Shannon index).

Dosage & Administration

Dose: 0.5% acetic acid solution (dilute apple cider vinegar).
Administration: Topical forearm soaks for 10 minutes daily over 14 days. Each participant served as their own control (split-arm design), with one arm receiving ACV and the other water.

Results & Efficacy

Microbiome Composition: No significant change in AD patients’ skin microbiome after ACV (p = 0.056) or water (p = 0.22) soaks.
S. aureus Abundance: No reduction in ACV-treated forearms (p = 0.60).
Microbiome Diversity: No significant differences in alpha diversity (Shannon index) between AD and healthy controls post-treatment (p = 0.14–0.21).
Comparative Efficacy: At 2 weeks, AD patients’ microbiomes were not significantly distinct from healthy controls (p = 0.05–0.21).

Limitations

Small Sample Size: Only 22 participants (11 AD, 11 controls), limiting statistical power.
Short Duration: 14-day intervention may be insufficient to detect long-term microbiome shifts.
Single Concentration: Tested only 0.5% acetic acid; higher concentrations might yield different effects.
Non-Blinded Design: Potential for bias due to participants’ awareness of treatment arms.
Lack of Clinical Outcomes: Did not assess disease severity (e.g., Eczema Area and Severity Index) or skin barrier function.
Single Institution: Findings may lack generalizability.

Clinical Relevance

For individuals with AD, daily 10-minute soaks in 0.5% ACV do not appear to beneficially alter skin microbiota or reduce S. aureus colonization. While ACV is often touted as a natural remedy for skin conditions, this study suggests it may not modulate the microbiome effectively at this concentration. However, the research does not rule out potential benefits of ACV on skin pH, hydration, or immune responses, which were not measured. Patients should prioritize evidence-based treatments (e.g., emollients, topical corticosteroids) and consult healthcare providers before using ACV as a primary intervention. Future studies are needed to evaluate higher ACV concentrations, prolonged use, and clinical endpoints.

Source: PubMed (2021), UVA IRB-HSR #19906.