To study the effect of fractionated 1927-nm non ablative thulium laser in reduction of post inflammatory hyperpigmentation (PIH) using a validated and reproducible model for studying PIH.

• Determine if there is aa reduction in PIH in patients treated with three (3) monthly sessions of fractionated 1927-nm non ablative thulium laser
• Determine if there is efficacy of post-procedure clobetasol propionate 0.05% ointment in the management of PIH
• Determine the histological and molecular changes that occur with laser and laser plus topical steroid treatment compared to untreated skin

The design of the study consists of a total of six visits including one initial screening visit within 107-127 days depending on the scheduling of your screening and subsequent visits. Assessments such as visual examination, photography, Investigatory Global Assessment (IGA) of pigmentation and erythema; Colorimetry; and Diffuse Reflectance Spectroscopy of the intended treatment area will be conducted at Visits 1-5. Optional biopsies will be taken at various time points.

Inclusion Criteria:

• Patient age 18 and older
• Patient with skin phototypes IV-VI
• Patient able to understand requirements of the study and risks involved
• Patient able to sign a consent form
• Patient to have discontinued all oral medications used to treat pigmentary abnormalities and all topical medications, except for sunscreen, used to treat pigmentary abnormalities on the buttocks one month prior to treatment

Exclusion Criteria:

• A patient who has skin dyspigmentation, birth marks, tattoos, or other skin findings at baseline on either buttock that may obscure study results
• A patient who is lactating, pregnant, or planning to become pregnant