الفهرس 
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Abstract
Melasma is a common, acquired, circumscribed hypermelanosis of the sun-exposed skin (Hexsel et al., 2009).
It presents as symmetric, hyper pigmented macules having irregular, serrated, and geographic borders. The most common locations are the cheeks, upper lips, the chin, and the forehead, but other sun-exposed areas may also be occasionally involved. It is known that melasma occurs in all population groups. However, epidemiological studies have reported higher prevalence among more pigmented phenotypes, such as East Asians (Japanese, Korean and Chinese), Indian, Pakistani, Middle Eastern and Mediterranean-African.
Several factors have been implicated in the etiology of melasma. These are genetic predisposition, UV radiation, thyroid disease, pregnancy; oral contraceptive pills (OCPs) and drugs such as phenytoin (Moin et al., 2006).
Recent data showed that melasma lesions have more vascularization as compared to the perilesional normal skin (Kang et al., 2010).Increased expression of vascular endothelial growth factor (VEGF) in keratinocytes was suggested as the major angiogenic factor for altered vessels in melasma(Kim et al.,2005).
Chronic UV accumulation lead to vascular dilatation and endothelia cells proliferation results in telangiestasia. Leakage of vascular componentsleads to activation of arachidonic acid and prostaglandins synthesis. This result in stimulation of melanization and vicious cycles of more vascular proliferation. This visious cycle is the driving force for persistence of melasma.
Diagnosis of melasma clinically, histopathological, Wood’slamp examination and by dermoscope.
-The aim of the work is to use dermoscope to prove presence of telangectasia in patients with melasma and its percent, so we can direct the treatment of melasma not only toward melanin and hyper pigmentation but also toward vascular component and telangectasia in melasma to decrease relapse and recurrence.
-About 300 female patients enrolled for thisobservational, descriptivestudy. A detailed history of the patient including age, address, education, occupation; duration and extent of melasma, history of having used any topical depigmenting agent or other methods of treatment . History of intake of any systemic drugs also recorded.
Clinical naked eye examination had been done recording the color of melasma and its pattern of involvement, also examination with dermoscope had been done to every patient to detect presence of telangectasia.Dermoscopic images were captured with a Sony digital camera equipped with a Dermlitedermoscope.
-we found that more than half of the patient had telangectasia158(52.2%), the older and the more duration of the disease the more likely to had telangectasia.
-Treatment targeting vascularization may prevent the relapse of melasma at least in some patients. The best treatment method remain to determind,but the use of topical, oral and\or physical approaches targeting the vascular component appear to be of great interest.