Chemical vitiligo: A subset of vitiligo

Abstract

Chemical leucoderma, an under-diagnosed common condition often mimicking idiopathic vitiligo, represents an acquired depigmentation induced by repeated exposure to specific chemical compounds in subjects with genetic susceptibility to vitiligo. This has been increasing rapidly in incidence in recent decades in developing countries like India. The term 'chemical vitiligo' was first coined by us to indicate the possible relationship between chemical leucoderma and vitiligo, which has been supported recently by other authors to designate the term 'chemical-induced vitiligo'. The largest case series showed that household chemical exposure was the major etiological factor. Causative chemicals are mostly phenolic and catecholic derivatives. Vitiligo pathogenesis is induced by genetic and environmental factors like many other autoimmune diseases. Innate immunity acts as a bridge between cellular stress and adaptive immunity. Multiple patches are commonly seen; children below 12 years are also affected in good numbers. The most common presence of confetti macules indicates these as characteristic, although not pathognomonic, of chemical leucoderma. Chemical leucoderma has been broadened into 'chemical leucoderma syndrome' with proper staging. The clinical criteria for diagnosis of chemical leucoderma have been specifically outlined. Same pathomechanism of chemical leucoderma might elucidate trigger factors and reasons for progression and chronicity in idiopathic vitiligo. Depigmentation in chemical vitiligo spreads to distant sites, in the same way as generalized idiopathic vitiligo. The study showed that chemical triggering factors played a very significant role in the induction and progression of vitiligo. Thus it should be rational to consider chemical vitiligo not as a separate entity but as a major subset of vitiligo spectrum.

The two faces of mast cells in vitiligo pathogenesis

“…Recent reports have shown that epidermal cytokine imbalance plays an important role in the induction of hypomelanotic lesion formation. A significant increase in the expression of inflammatory cytokines, such as IL6, TNF-α, IFN-γ, or IL2, and ET-1 or SCF expression reduction show melanocyte-stimulating activity [9,[18][19][20]. Recently, an outbreak of RDIL occurred in Japan, resulting in social impact and interest in the precise analysis of the pathogenesis and development of effective treatments for similar refractory vitiligo [5,6].…”

Research status of vitiligo models

“…Later, it was found that some commonly used daily necessities, such as disinfectants, diaper creams, cosmetic dyes, etc., can also cause skin discolorations. These chemically-induced depigmented spots were named "chemical vitiligo" by Ghosh, which is defined as acquired depigmentation caused by repeated exposure to a specific compound in genetically susceptible individuals, which is similar to idiopathic vitiligo [2].…”

Role of chemical exposure in the incidence of vitiligo: a case–control study in Tunisia

“…Several experimental evidences have shown that melanocytotoxic chemicals, especially phenolic and catechol derivatives, could cause vitiligo [ 4–7 ]. To our knowledge, few epidemiological studies are available on vitiligo induction factors and particularly on the role of exposure to chemicals in the onset of the disease has been found [ 8 ]. Therefore, there is a need to investigate the relationship between vitiligo and chemical exposures in order to understand this mysterious disease.…”