Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Dermatology and Venerology

Background:Macular amyloidosis (MA)and Post-inflammatory hyperpigmentation (PIH) are common causes of cutaneous hyperpigmentationthat are usually diagnosed clinically.However, sometimes their presentations are atypical and their differentiationis difficult. Dermoscopy is a valuable diagnostic tool of cutaneous pigmented diseases accordingly, it might be aid in their diagnosis. Objective:The present study aimed to describe characteristic dermoscopic features of MA and PIH together with histopathological correlation and to differentiate between these conditions in a non-invasively way. Methods:Fifty two patients with MA (n=26) and PIH (n=26)were enrolled in the current study. All patients were diagnosed histopathologically by H&E and Congo red stains.Detailed history, cutaneous examination and dermoscopic assessment 2using a hand-held and video dermoscopy3 were done.Results: In MA group the lesions were bilateral (84.6%), symmetrical (76.9%) with rippled pattern (96.2%) and in PIH group lesions were bilateral (73.1%), symmetrical (50%) with rippled pattern (42.3%) showing stastically signficant difference in symmetry (p=0.044) and rippling (p=<0.001).Two dermoscopic {uFB01}ndings were observed;A whitish central hub that was foundin MA patients (49.04±31.75) and to lesser extent in some cases of PIH (14.42±20.17) with significant difference (p=< 0.001) surrounded by peripheral pigmentation;its pattern tends to be ring and cluster in MA (p=0.048, 0.002 respectively)and reticulate in PIH(p=<0.001)

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