The vascular characteristics of melasma.

BACKGROUND: The pathogenesis of melasma is not yet fully understood. Previous studies indicate that dermal environment such as fibroblasts may have an important role in the development of melasma. Recently, it has been suggested that interactions between the cutaneous vasculature and melanocytes might have an influence on the development of pigmentation.

OBJECTIVES: We investigated the vascular characteristics in melasma lesions. The expression of vascular endothelial growth factor (VEGF), a major angiogenic factor of the skin, was also investigated in melasma.

METHODS: Erythema intensity was quantified by the increase of the a* parameter using a colorimeter. Skin samples were obtained from lesional and non-lesional facial skin of 50 Korean women with melasma. Immunohistochemistry was performed to determine the expression of factor VIIIa-related antigen and VEGF in melasma.

RESULTS: The values of a* was significantly higher in the melasma lesion than that of perilesional normal skin. Computer-assisted image analyses of factor VIIIa-related antigen-stained sections revealed a significant increase of both the number and the size of dermal blood vessels in the lesional skin. There was significant relationship between the number of vessels and pigmentation in melasma. The expression of VEGF was significantly increased in melasma

CONCLUSIONS: These data suggest that increased vascularity is one of the major findings in melasma. VEGF may be a major angiogenic factor for altered vessels in melasma.