Post-inflammatory hyperpigmentation (PIH) is an acquired hyper melanosis that occurs after cutaneous inflammation or injury frequently affecting darker skinned individuals. Bakuchiol is derived from plants and has inhibitory effects on melanin synthesis, which makes it a promising therapeutic intervention in the management of PIH. This study aims to evaluate the efficacy of bakuchiol in treating post inflammatory hyperpigmentation using the investigators previously validated model in comparison to acne induced PIH.

Post inflammatory hyperpigmentation (PIH) is an acquired hyper melanosis that occurs after cutaneous inflammation or injury. This process can occur in all skin types but more frequently affects darker skinned patients, such as African Americans, Hispanics, Asians, Native Americans, Pacific Islanders and those of Middle Eastern descent. PIH can occur after infection, allergic reactions, contact dermatitis, some medications, burns, following procedures, or inflammatory disease such as acne. In skin of color, PIH frequently occurs in resolving acne lesions and can persist for months after the acne lesion itself has disappeared. In many cases, the resulting PIH can be more distressing than the original insult.

During the investigators previous study on an in-vivo model for post-inflammatory hyperpigmentation, the investigators investigated the clinical, spectroscopic and histologic characteristics of acne-induced PIH versus irritant induced PIH using Trichloroacetic acid (TCA), 35% solution. From this initial study, the investigators concluded that the similarity of Investigator's Global Assessment scores, and spectroscopic measurements using Diffuse Reflectance Spectroscopy and Colorimetry in both acne and TCA-induced PIH at Day 28 suggest that TCA-induced PIH could be a reproducible model for acne induced PIH.

Bakuchiol is a meroterpene phenol derived from plant sources, such as the leaves and seeds of Psoralea corylifolia and the fruits of Piper longum. It has been reported to have anti-inflammatory, anti-bacterial, and antioxidant properties, as well as cause improvement in photodamaged skin. In-vitro studies on melanin production showed that bakuchiol had inhibitory effects on melanin synthesis, which make it a promising therapeutic intervention in the management of PIH.

This study aims to evaluate the efficacy of bakuchiol in treating post inflammatory hyperpigmentation using the investigators previously validated model in comparison to acne induced PIH.

Inclusion Criteria:

• Patients with types IV-VI skin
• Minimum age of 18 years
• Able to understand requirements of the study and risks involved
• Able to sign a consent form.
• Existing facial acne pustules (at least three on the face) with history of post-inflammatory hyperpigmentation

Exclusion Criteria:

• Patients with a recent history of vitiligo, melasma, and other disorders of pigmentation with the exception of PIH judged to be clinically significant by the investigator
• Patients with a history of cystic acne or acne conglobate
• Patients on systemic antibiotics or keratolytics (isotretinoin, etc), or topical antibiotics or keratolytic use (retinoids, benzoyl peroxide) over target areas who are unwilling to stop these medications for the duration of the study.