Familial and Genetic Factors
Approximately 30% of patients have a family history of the condition, which may involve multiple gene variations. These variations may also overlap with those of other autoimmune diseases, such as thyroid disorders, type 1 diabetes, and rheumatoid arthritis. Patients should undergo blood tests and medical evaluations to confirm the presence of any concurrent autoimmune diseases.

Oxidative Stress and Melanocyte Abnormalities
Melanocytes in vitiligo patients are more susceptible to oxidative stress, leading to the release of reactive oxygen species (ROS). ROS are harmful; their accumulation induces DNA damage, protein oxidation and fragmentation, and lipid peroxidation. This disrupts normal cellular functions and triggers a cascade of imbalances in antioxidant mechanisms. Consequently, the melanocytes of vitiligo patients become increasingly fragile and sensitive. Both external and internal stressors can trigger vitiligo:

External Stressors: Include ultraviolet radiation and monobenzone (an organic compound that destroys melanocytes, causing permanent depigmentation).

Internal Stressors: Include the production of large amounts of misfolded proteins during melanogenesis, dysregulated melanocyte autophagy, the loss of the nuclear factor E2-related factor 2 (Nrf2) pathway's protective function against oxidative stress, and mitochondrial dysfunction. Mitochondria are vital powerhouses of the human body, supplying the essential energy required for normal cellular function. Mitochondrial dysfunction leads to increased ROS-induced cellular damage and triggers melanocyte apoptosis in cells that heavily rely on mitochondrial function.

Immune Response and Inflammation

Oxidative stress places pressure on both stressed melanocytes and stressed keratinocytes, prompting them to release pro-inflammatory factors that recruit T cells to the white patch lesions on the skin. Both the innate and adaptive immune systems are closely linked to the pathogenesis of vitiligo, with cytotoxic CD8+ T cells considered the primary culprits that attack and destroy melanocytes. Active T cells can be found in the skin lesions of patients, continuously attacking melanocytes. Even after white patches form, T cells persist within the skin, hindering the recovery and regeneration of melanocytes.

Various pro-inflammatory cytokines are derived through CD8+ T cells at the vitiligo lesions, including interferon-γ-induced CXCL9, CXCL10, and CXCL11:

CXCL9 promotes the accumulation of a large number of T cells at the lesion sites.

CXCL10 pinpoints the location of melanocytes for T cell attacks.

Research has found that neutralizing CXCL10 can induce repigmentation in vitiligo lesions. In animal studies, targeting CXCR3 (the receptor for CXCL9 and CXCL10) successfully reduced T cell numbers and reversed vitiligo conditions.