repigmentation

Repigmentation is the restoration of pigment in skin that has lost color due to conditions such as vitiligo, postinflammatory hypopigmentation, or other hypopigmentary disorders. In vitiligo, depigmentation typically results from loss of melanocytes in the epidermis. Repigmentation occurs when melanocytes or their precursors repopulate the epidermis and resume melanin production.

Repigmentation patterns reflect the sources of pigment cells. It often begins in the perilesional skin and may spread outward from hair follicles, a process called perifollicular repigmentation. Melanocytes in the hair follicle bulge and outer root sheath can migrate into the epidermis, contributing to new pigment. In some cases, residual epidermal melanocytes can proliferate and reestablish color in adjacent areas. The speed and extent of repigmentation vary and may be incomplete or patchy.

Therapies aimed at stimulating repigmentation include phototherapy, particularly narrow-band ultraviolet B (NB-UVB) and, less commonly, psoralen plus ultraviolet A (PUVA). These treatments promote melanocyte proliferation and migration and are often used for facial or widespread vitiligo. Topical agents such as corticosteroids or calcineurin inhibitors may help in selected lesions, especially early or less extensive disease. Surgical approaches, including melanocyte-keratinocyte transplantation, noncultured epidermal cell suspension, and blister grafting, are options for stable unresponsive patches and rely on introducing functioning pigment cells into depigmented areas.

Prognosis varies with disease form, location, and duration. Facial lesions and smaller patches respond more readily; leukotrichia (depigmentation of hair) suggests a poorer prognosis. Repigmentation can take months and may be incomplete or relapsed after treatment cessation.