Confocal Microscopy in Diagnosis and Management of Melasma: Review of Literature

Abstract

Background: Melasma is a common acquired disorder of hyperpigmentation mainly located on the face. Classification and clinical evaluation of melasma is the first step of any therapeutic strategy. Reflectance Confocal Microscopy (RCM) is a novel, non-invasive technique that offers an in vivo analysis of the skin layers at a cellular level resolution. Objective: To assess the efficacy of the application of RCM in the diagnosis and management of melasma. Methods: A search of all the available literature concerning the use of RCM in melasma was performed on Pubmed Medline. In total ten papers were selected and reviewed. Results: Melasma seems to exhibit a specific pattern in RCM analysis. Correlation of histopathology and RCM revealed common findings among the relevant studies. Epidermal hyperpigmentation – a hallmark of melasma - is represented as a honeycombed pattern, mottled pigmentation and strongly visible papillary rings around the dermal papillae, composed by a sequence of brighter cellular structures at the level of the dermo-epidermal junction. Dermal melanin has the appearance of plump bright particles corresponding to melanophages. RCM reveals an epidermal portion in all melasma lesions rendering obsolete the up to present classification of the disease, which is based on Wood’s lamp examination. Even clinically undetectable changes during melasma treatment can be detected by means of RCM analysis introducing the technique as a highly sensitive tool for the monitoring and evaluation of treatment. Conclusion: RCM emerges as a reliable adjuvant technique for the classification, diagnosis and overall management of melasma. Further studies need to be conducted in order to investigate the prospective of in vivo RCM in melasma.