Apple Cider Vinegar Soaks [0.5%] as a Treatment of Atopic Dermatitis Do Not Improve Skin Barrier Integrity

To study the effect of dilute apple cider vinegar (ACV) soaks on skin barrier integrity by measuring skin transepidermal water loss (TEWL) and skin pH in subjects with atopic dermatitis (AD).

The study included a total of 22 subjects recruited at the University of Virginia. Eleven of the subjects with AD and eleven healthy controls, age ≥12 years, enrolled between June 2017 and October 2017.

A split-arm pilot study recruiting subjects older than 12 years of age with AD and healthy controls was performed. Exclusion criteria included the use of topical or systemic antimicrobial agents in the past month. However, other treatment methods such as, topical steroid use were permitted and documented. Subjects in both groups were randomly assigned to soak one forearm in dilute ACV (0.5% concentration acetic acid) and the other forearm in tap water for 10 minutes a day for 14 days. Tewameter TM 300 (Courage+Khazaka Electronic) quantified forearm TEWL and the Skin pH Meter PH 905 (Courage+Khazaka Electronic) was used to measure skin pH levels. Baseline measurements were taken at the first study visit, as well as at 0, 15, 30, 60 minutes after the first soak and 24 hours after completing 14 days of daily 10-minute soaks. The subjects also self-reported scaled skin symptoms during the length of the study.

At baseline, TEWL was significantly higher in AD subjects (TEWL 11.1 [8.6–14.3] g/m²/h) compared with healthy controls (TEWL 7.1 [6.0–8.4] g/m²/h). Skin pH was similar in AD (pH 4.88 [4.67–5.10]) and healthy control subjects (pH 4.86 [4.60–5.13]). After ACV treatment, TEWL increased and pH decreased at 0- and 15-minutes post-ACV treatment in both subject groups. However, by 60 minutes post-ACV both groups had returned to baseline TEWL. Furthermore, when comparing the ACV or tap water arm, there was no significant change in TEWL. Skin pH shifted significantly to an alkaline pH in subjects with AD (pH 5.54 [5.16–5.94]) following tap water soak compared with healthy control subjects (pH 5.23 [4.91–5.59]) (P ≤ .01). The addition of ACV to tap water resulted in similar pH levels in both subject groups immediately after the soak. These results were not long-standing as skin pH was comparable to baseline at day 14 (P = .49). The majority of subjects (16/22) did report mild forearm skin discomfort, predominantly limited to the ACV-treated arm. One AD subject did experience severe skin symptoms that resolved within 2 days of stopping ACV soaks. Additionally, one healthy control subject did experience a nonpruritic papular rash that self-resolved.

The use of dilute ACV soaks had no significant effects on TEWL and skin pH on the skin of subjects with AD. The majority of subjects did experience skin irritation.

Families will often use natural treatment options for various disorders including AD. The study suggests that the use of dilute ACV on patients with AD is not effective in the improvement of skin barrier integrity and may actually provoke irritation to the skin. While the authors did recognize the small number of subjects and need for more diversity among participants including more children, the study does provide some scientific evidence of the effect of ACV on the skin.