Excimer Light Treatment for Idiopathic Guttate Hypomelanosis: A Pilot Study

Methods: This pilot study will consist of 10 adult subjects with symmetric IGH on the lower legs. After enrollment, 5 lesions of IGH on each leg will be selected by either Dr. Jennifer Gordon or Dr. Ammar Ahmed and marked. Subjects will be randomized to which extremity (right or left) will be treated. Treatments with the Xtrac Excimer laser (wavelength of 308nm) will be performed twice weekly for 12 weeks using the typical vitiligo protocol (see Appendix C). Photographs of both extremities will be taken prior to initial treatment and then every 4 weeks. The photographs will be analyzed by two separate, blinded dermatologists and rated on improvement from baseline using the following scale: 1= worsening of IGH; 2= no improvement (IGH remained stable); 3= mild improvement of IGH (some repigmentation on <50% IGH); 4= moderate improvement (some repigmentation on >50% or full repigmentation on <75% IGH); 5= full repigmentation on >75% IGH (see Appendix A). Subjects will also be asked to complete this survey subjectively every 4 weeks. Internal control will be represented by the marked lesions on the non-treated extremity of each patient. Control versus treatment groups will be statistically compared; however, due to the limited number of patient in this pilot study, a descriptive trend analysis will likely be completed. Subjects will be compensated $10 per visit (totaling $250). If a subject withdraws early from the study, they will be compensated for every completed visit. The 25th visit will consist of final photographs and surveys, and will not include treatment.

Statistical Analysis: The main outcomes to be collected are the improvement of IGH from baseline at weeks 4, 8 and 12 by the blinded dermatologists and by the subjects. Subjects will be stratified by Fitzpatrick skin type for analysis as well.

• Excimer Light Treatment (Device), also known as Xtrac, Excimer laser, phototherapy: Excimer light treatment will be performed on one leg of every subject as the intervention while the subjects other leg will serve as a control

Primary outcomes

• Efficacy Outcome [12 weeks]: Effectiveness will be graded by the blinded observer scal via photographic comparisons at the end of the study. Efficacy was assessed by improvement from baseline using the following scale: -1 = Worsening of IGH; 0 = No Improvement (IGH remained stable); 1 = Mild improvement of IGH (some re-pigmentation on <50% IGH); 2 = Moderate improvement (some re-pigmentation on >50% or full re-pigmentation on <75% IGH); 3 = Full re-pigmentation on >75% IGH.

Secondary outcomes

• Subject Self-reported Assessment of Re-pigmentation for Treated Lesions [12 weeks]: Subject reported level of re-pigmentation for treated lesions was assessed by improvement from baseline using a scale from 1 - 4 with 1 being the least amount of re-pigmentation and 4 being the most re-pigmentation: 1 = Worsening of the light spots that were treated (the light spots seem to have gotten lighter or I have more light spots in the areas that were treated); 2 = No Improvement of the light spots (light spots have not changed since starting this study); 3 = Mild improvement of the light spots (there is some darkening of the light spots, but not in more than half of them); 4 = Moderate improvement (there is some darkening of the light spots in more than half of the light spots, but not more than 75% of them).

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria

* Diagnosis of idiopathic guttate hypomelanosis on the bilateral lower extremities with at least 5 lesions on each leg that are overall symmetric as determined by study personnel
* Patients must be 18 years or older
* Patients may be from any ethnicity but are required to be English-speakers
* Patients must provide written informed consent to participate in the study

Exclusion Criteria

* Patients with pre-existing dermatological condition that is exacerbated by ultraviolet radiation
* Non-English speakers
* Patients taking medications known to have potential phototoxic reactions
* Use of Ultraviolet tanning beds, Ultraviolet-A, Ultraviolet- B or excimer therapy within the previous 3 months on the lower extremities
* Current or previous treatment within the past 3 months specifically for IGH
* Pregnancy or pregnancy within the past 3 months (this can cause changes in pigmentation)

Participant flow

Outcome results

• Efficacy Outcome (Primary), Mean, units on a scale: Excimer Light Treatment 2.31 (2.08 to 2.54); Control 1.15 (0.92 to 1.39)
• Subject Self-reported Assessment of Re-pigmentation for Treated Lesions (Secondary), Mean, units on a scale: All Patients 4.5 +/- 0.223

Adverse events

Time frame: 12 weeks

Limitations and caveats: Limitations included a small sample size with minimal variation in Fitzpatrick skin type, an all-female pool, and lack of extended follow-up.

• Ammar Ahmed, MD, Principal investigator, Seton Healthcare Family