Topical TCA and Methoxsalen Not Clinically Effective for Acral Vitiligo

Image Credit: © dermnetnz.org

A new study compared the clinical efficacy of topical trichloroacetic acid 70% (TCA) versus methoxsalen 0.2% paint for stable acral vitiligo on the hands and feet.¹ These areas are more resistant to topical therapies, due to the tissue structure, repetitive friction, and thicker stratum corneum.² However, there was no or mild clinical response with each treatment and patients were unsatisfied with outcomes.

Eligible participants (28 males and 42 females) who had not received any treatment for vitiligo in the previous 3 months were included in the trial. All were between the ages of 10 and 50 years. The median age for the TCA group was 19 while the methoxsalen group had a median age of 25.

Each patient also had a Vitiligo Disease Activity (VIDA) score of ≤ 0 with clear-edged, pigmentated lesions. Clinicians recorded information on disease history, past drug use, and family history. Each patient was also provided with a Wood’s lamp and a Dermoscopic exam to confirm vitiligo diagnosis. The median disease duration was between 4 and 5 years.

Participants were randomly and evenly divided into 2 groups, with 35 patients in each. They were also designated by whether or not they had foot or hand lesions. Group A applied a thin layer of topical 0.2% methoxsalen every other day. Group B received 1 to 3 passes of topical TCA 70% at a clinic every 2 weeks. TCA is believed to repigment vitiligo patches due to the induction of inflammation of viable melanocytes.³ Conversely, the botanic psoralen of methoxsalen sensitizes the skin to ultraviolet A light.⁴

The treatment duration was 4 months along with dermoscopic follow-up. Photographs were taken at baseline, 4 weeks, 8 weeks, and 3 months after treatment. Repigmentation was evaluated on a 4-point scale with an “excellent” evaluation of > 75% being the highest score. Dermoscopic regimentation was also classified into 4 patterns; perifollicular, marginal, diffuse, and mixed.

In the group of patients using TCA treatment, the mean improvement was 4.0 ± 11.6% with a range of 0 to 60%. In the methoxsalen group, the mean improvement was 0.57 ± 3.3% with a range of 0 to 20% (p = 0.051). There was no statistically significant difference between the 2 groups. Additionally, the patterns of repigmentation did not differ significantly among both cohorts (p = 0.329).

Due to this little to no clinical response, patient satisfaction was relatively poor. In the TCA group, 83% of patients were not satisfied as were 97% of patients in the methoxsalen group. There were some mild adverse events of irritation and desquamation with both cohorts, but the treatments were significantly tolerated.

The study did have several limitations. These include the small sample size, use of 1 university clinic, short follow-up period, and the focus on only one type of vitiligo. In further research, a larger approach utilizing many locations may improve the generalizability of the results.

“To achieve ideal therapeutic efficacy, a future treatment rationale using larger multicenter studies and varied concentrations and enhanced delivery approaches is essential to explore the promising potential and improved outcomes of the above used treatments,” the authors concluded.

References

1. Elshahed AR, Ammar AM, Ali AM, Elsaie ML. Clinical and dermoscopic assessment of the efficacy of topical trichloroacetic acid 70% versus methoxsalen 0.2% paint in stable acral vitiligo. Sci Rep. 2025;15(1):4756. Published 2025 Feb 8. doi:10.1038/s41598-025-88811-w

2. Wang X, Wu W, Chen J, Li C, Li S. Management of the refractory vitiligo patient: current therapeutic strategies and future options. Front Immunol. 2024;14:1294919. Published 2024 Jan 4. doi:10.3389/fimmu.2023.1294919

3. Razmi, T. M., Kumaran, S. M. & Parsad, D. Trichloroacetic acid 25% Peel to facilitate dermabrasion at difficult sites in Vitiligo surgery. Dermatol. Surg. 45(5), 750–752 (2019).

4. Maitray A, Rishi P. Methoxsalen-induced macular toxicity. Indian J Ophthalmol. 2017;65(11):1243-1245. doi:10.4103/ijo.IJO_413_17