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Unmasking Facial Melanosis: A Prospective Clinico-Dermoscopic Study
Sheethal K Jose1, Priya Sara Kuryan1, Diya Katrina Koikkara1
1Department of Dermatology Venereology and Leprosy, Christian Medical College, Vellore, India.
Introduction:
Various entities of acquired facial melanosis present with considerable clinical overlap, posing diagnostic challenges. Dermoscopy is being increasingly used in its diagnosis.
Objectives:
To assess dermoscopic and clinicopathological features of facial melanosis in Fitzpatrick skin types IV-VI.
Methods:
A prospective cross-sectional study of clinical and dermoscopic features of facial melanosis-lichen planus pigmentosus (LPP), pigmented contact dermatitis (PCD), and facial acanthosis nigricans (FAN)-was conducted. Melasma, periorbital hyperpigmentation, and nevus of Ota were excluded.
Results:
Fifty-six patients were included: 31 (55.4%) with LPP, 18 (32.1%) FAN, and seven (12.5%) PCD. Clinically, LPP showed significantly more involvement of face (55.2 ± 22.2%) (P=0.029), especially the chin (29, 93.5%) (P=0.006). Dermoscopy revealed more than one pattern of pigment structures in 54 (96.4%) patients. Predominant patterns in LPP were reticular (21, 67.7%), peppered (15, 48.4%), and annular (13, 41.9%). There was an overlap of patterns like annular, annular-granular, and reticular in both LPP and PCD. Peppered (15, 48.4%) was significantly more in LPP (P=0.023), while linear dots were seen exclusively in LPP (4, 12.9%); smudged was significantly more in PCD (6, 85.7%) and FAN (15, 83.3%) (P=0.003). Concentric circles (16, 88.9%) and parallel lines (14, 77.8%) were significantly more in FAN (P<0.001 each), while crypts-gyri (10, 55.6%) and papillary projections (8, 44.4%) were seen exclusively in FAN. Combination of dots and clods was also significantly more in LPP (26, 83.9%; P=0.007), whereas blue-gray pigmentation (19, 61.3%) was observed exclusively in LPP.
Conclusion:
Distinct dermoscopic features aid in differentiating acquired facial melanosis. Blue-gray dots and clods in peppered, reticular, and linear dots patterns favor LPP, while concentric circles, parallel lines, crypts-gyri, and papillary projections suggest FAN. Recognition of these patterns may obviate biopsy in cosmetically sensitive areas.