Glycerol 85% efficacy on atopic skin and its microbiome: a randomized controlled trial with clinical and bacteriological evaluation

Abstract

Background: Treating atopic dermatitis (AD) is still a challenge. The staphylococcal skin load is known to aggravate AD. Narrow band ultraviolet B (NB-UVB) and glycerol in low concentration (20-40%) are established therapies for AD. NB-UVB has proven antimicrobial actions, while high concentration glycerol (85-100%) showed similar effects in vitro but has not been clinically tested.

Objective: To evaluate the efficacy and tolerability of concentrated glycerol 85% compared to NB-UVB in patients with AD, as assessed by clinical improvement and reduction of staphylococcal colonization of the skin.

Methods: 30 patients with mild to moderate AD were randomized into either NB-UVB or glycerol 85% group. Patients were treated for one month and followed for an additional month. Swabs were taken from the skin and nose to be cultured on mannitol-salt agar for Staphylococci and quantified to determine Colony Forming Units.

Results: Both groups showed statistically insignificant microbial changes and statistically significant clinical improvement after treatment. The results were comparable between both groups.

Conclusions: Concentrated glycerol 85% is a cheap effective readily accessible alternative for phototherapy in patients with mild-moderate AD who cannot access the facility. Reduction of staphylococcal skin load seems to be involved, but its role is minimal.

Keywords: Atopic dermatitis; glycerol; microbiome; phototherapy; staphylococcus; ultraviolet therapy.