الفهرس 
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Abstract
Melasma is a common type of pigmentary disorders. Multiple factors have been implicated in the pathophysiology of melasma, including genetic background, exposure to ultraviolet radiation, female sex hormones, pregnancy, hormonal activity, oral contraceptives, thyroid dysfuntion, antiepileptic medications, and cosmetic products. Complex interactions between predisposing genetic and environmental factors act as triggers for disease progression. Accordig to Wood’s light examination melasma is classified into: (1) an epidermal type, (2) a dermal type, (3) a mixed type, and (4) an indeterminate type.
Some investigators have reported an association between low serum zinc levels and a variety of dermatological conditions.
Zinc has antioxidative and anti-inflammatory properties, which may act as a regenerative substance in damaged skin. It can also protect skin from ultraviolet radiation, especially irritated skin, and so may prevent extra activity of melanocytes. These mechanisms make zinc has a role in prevention of melasma.
Zn (II) also modulates melanogenesis, but the net effect is unclear. Zn (II) inhibits tyrosinase in vitro, but also enhances dopachrome tautomerase activity (Trp2). It is well documented that oral ingestion of Zn (II) affects the degree of pigmentation and the melanosome structure. High doses of zinc sulfate inhibit eumelanogenesis and cause severe murine hair hypopigmentation. On the other hand, low zinc diets produce abnormal large melanosomes in choroidal melanocytes of adult pigs resulting in unusual and aberrant melanin distribution. The balance of copper to zinc is perhaps more important than the concentration of either of these ions.
In the present study, the aim was to evaluate serum level of zinc in patients with melasma. The patients were selected from Dermatology, Venereology and Andrology Outpatient Clinic of Zagazig University Hospitals during the period from from February 2018 till august 2018.
The seventy two patients involved in this study and seventy two age and sex matched healthy controls were checked for their serum zinc level (to determine if zinc deficiency contribute to development of melasma).
The seventy two female melasma patients involved in the present study had mean age of (37.24±6.25) years.
Analysis of family history of the studied cases has revealed that family history of melasma was positive in 29 cases (40.3%) and negative in 43cases (59.7%).
This study showed that patients with melasma had mean serum zinc level of (83.47± 22.28)µg/dl, while controls had mean level of (92.63 ± 13.63) µg/dl, with significant difference between patients and controls as p. Value = 0.000.
Also we found that serum zinc level show significant variations with respect to the grade of severity according to mMASI.
Recommendations
from the results of the current study, we recommend:
1. Subsequent cross-sectional studies with a large number of melasma patients are needed to clarify: Whether oral zinc supplementation play a role in treatment of melasma, its deficiency have a role in its pathogenesis?
2. Zinc supplementation might be a reasonable and specific treatment strategy in the future.