Pigmentation disorders can result from dysregulated changes in the number of melanocytes (MCs) or the function of melanocytes, such as abnormalities in melanin production, distribution, transport to the surrounding keratinocytes, or melanin degradation. Melanin synthesis is an energy-consuming process, which tends to form a pro-oxidative state and produces a large amount of reactive oxygen species (ROS) in MCs, therefore melanocytes are vulnerable to oxidative stress. Moreover, MCs are exposed to chronic oxidative stress with the irradiation of ultraviolet (UV), pollution, or other harmful factors.

When the balance between the pro- and antioxidant systems is broken, oxidative stress will cause DNA damage, biological metabolism dysregulation, and signaling pathways changes in MCs. In addition, the aberrant ROS accumulation in keratinocytes and fibroblasts could also contribute to pigmentation disorders by affecting MCs. Additionally, many herbal products and organic compounds with antioxidant functions have been found to alleviate pigmentation disorders.

In this Special Issue, we expect to explore the role of oxidative stress in pigmentation disorders and invite researchers to contribute original research or review articles aiming to discuss the oxidative stress-associated mechanisms, signaling pathways, and corresponding therapeutics in the pathogenesis and treatment of pigmentation disorders.

Potential topics include but are not limited to the following:

• The role of oxidative stress in pigmentation disorders: hyperpigmentation disorders including melasma, post-inflammatory hyperpigmentation (PIH), UV-induced pigmentation, etc.; hypopigmentation disorders including vitiligo, halo nevus, chemical leukoderma, dyspigmented hypertrophic scar, etc.; age-related pigmentation disorders, including seborrheic keratosis (SK), age-related macular degeneration (AMD), etc.; pigment cell tumors, especially malignant melanoma
• Basic molecular and cellular mechanisms focused on oxidative stress in pigmentation disorders
• The application of antioxidants or new therapeutics underlying oxidative stress in pigmentation disorders
• In vivo and in vitro studies focused on the mechanisms or therapeutics underlying oxidative stress in pigmentation disorders