Do oxidative stress and melanin accumulation contribute to the pathogenesis of idiopathic guttate hypomelanosis: A prospective case‐control study

Abstract

Background: Oxidative stress parameters have been reported to be significantly higher than controls in diverse disorders of pigmentation but no such data seem to be extant for IGH.Objectives: To verify whether heightened oxidative stress levels are seen in patients with IGH (compared with matched controls) and quantify the same in blood using appropriate biochemical markers. Further, an attempt to determine if there might be any correlation between the amount of oxidative stress and the severity of the disease. Methodology: This prospective case-control study was conducted in Northern India. Thirty Indian patients (Fitzpatrick skin phototype (SPT) IV-V) were included. The diagnosis of IGH lesions was confirmed based on characteristic clinical, and dermoscopic characteristics and confirmed on histopathological examination (H & E) of one of the lesions. Results:The oxidative stress enzyme level was significantly higher among the cases compared to controls which were statistically significant (p < 0.05). A positive correlation was also observed between the levels of these markers and number of lesions, but this finding was statistically not significant [p > 0.05]. Assessment of melanin level by Dopa staining method in the IGH lesions revealed irregularly distributed melanin with areas of high and low melanin content and greater accumulation in the basement layer. Conclusion:The results of this probably the first study evaluating oxidative stress in IGH show that the oxidative stress is increased in patients with IGH. Level of oxidative stress seems to be correlated with both age of the patient (more in the elderly) and number of lesions.

Melanocytes in idiopathic guttate hypomelanosis disappear and are senescent

“…Under photodamaged stress, the balance between prosenescent and pro-apoptotic pathways associated with p16, p53 and p21 may determine the fate of melanocytes, that is apoptosis versus senescence. 7 Accordingly, previous studies have shown that the oxidative stress enzyme level was higher in IGH 8 cases and that melanocytes from IGH patients have the morphological features of senescent cells. 9 Underlying dermal senescence may also contribute to the melanocyte loss and senescence in IGH.…”