# Treatment of Melasma Targeting Dermal–Epidermal Interactions Utilizing High‐Intensity, High‐Frequency Parallel Ultrasound Beam in Asian Skin

## TL;DR

A new ultrasound-based treatment called Thermal-Thread Technique significantly improved melasma in Asian patients over six months without side effects.

## Contribution

The study introduces a novel ultrasound-based treatment targeting dermal-epidermal interactions for melasma in Asian skin.

## Key findings

- The Thermal-Thread Technique significantly reduced melasma severity (mMASI score) six months post-treatment.
- No side effects were observed in 20 patients across multiple Fitzpatrick skin types.
- Improvement was consistent regardless of Fitzpatrick skin type.

## Abstract

Melasma is a multifactorial disorder, and while treatments aimed at suppressing melanin production and removing excess melanin have demonstrated some efficacy, no definitive therapy has yet been established. Dermal aging is widely recognized as a contributing factor in melasma, and previous studies have demonstrated that the presence of senescent fibroblasts reduces the efficacy of melasma treatments. Therefore, treatment strategies focused on reactivating fibroblast activity are anticipated to be effective against melasma.

The objective of this study is to investigate the safety and efficacy of the Thermal‐Thread Technique, which utilizes high‐intensity, high‐frequency parallel ultrasound beams for the treatment of melasma among Asian subjects.

Patients diagnosed with melasma, regardless of disease type, duration, or Fitzpatrick skin type, underwent a single treatment session covering the entire face utilizing a high‐intensity, high‐frequency parallel ultrasound beam with Thermal‐Thread Technique. High‐resolution skin images were captured using a skin analyzer before treatment and six months after the treatment. Two independent evaluators assessed these images using the modified Melasma Area and Severity Index (mMASI) scoring system to objectively evaluate treatment efficacy. Statistical analyses of the mMASI scores were performed using paired t‐tests. All potential side effects were carefully monitored both during and after the procedure.

All patients (n = 20, female, mean age: 50.5 ± 5.7) completed the study. The distribution of Fitzpatrick skin types among participants was as follows: type II (n = 7), type III (n = 11), and type IV (n = 2). The mean mMASI score significantly decreased from 4.63 ± 1.66 at baseline to 1.69 ± 0.90 six months post‐treatment (p = 1.53e‐9; p < 0.001). No statistically significant difference was observed among FST groups (F(2,17) = 1.68, p = 0.216). No side effects were observed or reported during or after the treatment period.

The improvement in mMASI scores observed with the Thermal‐Thread Technique, utilizing a high‐intensity, high‐frequency parallel ultrasound beam, demonstrates its potential as an effective treatment for melasma. Further research is necessary to evaluate its efficacy in more severe cases, extend the observational period, and investigate the potential benefits associated with multiple treatment sessions.