VALIDITY OF WOOD'S LIGHT IN MELASMA

Abstract

Melasma is a common disorder of macular facial hyperpigmentation, which can also affect the neck, namely sun-exposed areas. It usually affects females during childbearing age, but Melasma may also appear in 14%-25% of male population, more commonly affecting Indian males. Melasma was been reported during pregnancy however many other factors have been implicated in the etiology of melasma such as genetic predisposition with increased incidence among family members. Also UV light was believed to be an initiating factor for melasma due to its known effect on melanogenesis. Hormonal influence had its share in literature as it was reported that estrogen receptor expression increases in melasma affected skin. Many patients noticed melasma appearance after long time use of hormonal contraception. Other associations of melasma include certain cosmetic use, chronic Pelvic inflammatory disease especially due to Chlamydia trachomatis and co-existence of lentigines and melanocytic nevi. Lesions of melasma are irregular light to dark brown macules with different patterns of distribution including centrofacial pattern, malar pattern, mandibular pattern and other less common areas such as extensor forearm and shoulders. Melasma is classified according to Wood's lamp examination into epidermal, dermal, mixed patterns and indeterminate pattern. Histopathologically, melanin distribution is mainly in the basal and suprabasal layers. Severe solar elastosis was also found in some patients, and greater number of epidermal melanocytes were reported which were more active than their counterpart in perilesional skin. Melasma should be differentiated from postinflammatory hyperpigmentation and other causes of facial melanosis. Treatment includes general measures such as the proper use of sun screen and avoidance of sun exposure and cessation of hormonal contraception if used. Specific treatment includes topical therapy such as hydroquinon, topical retinoids or topical steroids. Combined topical treatment has proven its effectiveness for persistent types of melasma. Azelaic acid, kojic acid and ascorbic acid were previously introduced in literature for melasma treatment. Chemical peeling is an effective method of melanin removal using GA, SA or TCA. Other treatments include dermabrasion, intense pulsed light therapy, laser therapy, fractional resurfacing, and mesotherapy. Treatment of melasma is challenging due to resistance to respond and high incidence of recurrence after discontinuation of therapy. Thus, application of combined treatment modalities and use of maintenance therapy after resolution has always been mandatory. On the basis of both visible light and Wood's light examination, we detected 3 types of melisma in our study. Epidermal type exhibited enhancement of color contrast when examined with Wood's light as compared to visible light and were observed in 60% of patients. Dermal type of melasma exhibited no enhancement or accentuation of color contrast under the Wood's light observed in 30% of patients. Lastly the mixed type of melasma refers to those patients in whom Wood's light examination revealed both enhancement of lesions in some areas and no enhancement of lesions in other areas that was observed in 10% of patients.