Keerthi Jampani1, Swetha Jampani2

The aim of the present study was to analyse different clinical patterns of frictional melanosis and to evaluate whether sun exposure is a causative or contributing factor for frictional melanosis. Furthermore, histopathology with haematoxylin and eosin along with special stains for amyloid like Congo red was done.
50 patients with clinical diagnosis of frictional melanosis participated in this study.
Patients of all ages and both sexes with classical clinical features suggestive of frictional melanosis are included.
Patients having pigmentation over areas where the frictional melanosis presents classically but have been using chemicals, hair dyes and other agents which can cause photocontact dermatitis have been excluded from the study.
A detailed history regarding duration of illness, progression and precipitating factors along with detailed clinical examination regarding the location of the lesions and type of lesions was done and patients were subjected to skin biopsy after obtaining a written consent.
RESULTS Out of 50 cases, 39 (78%) were confirmed with histopathology as frictional melanosis and 11(22%) as macular amyloidosis. Among patients of frictional melanosis, 56.41% had only skin lesions. In macular amyloidosis 63.63% patients had itching along with skin lesions. In Frictional melanosis the most frequently involved site was extensor aspect of arm (78.48%). The most frequently involved site in macular amyloidosis was extensor aspect of forearm (93.34%).
In this study a total number of 50 patients with clinical presentation of frictional melanosis were analysed with female preponderance. Amyloid deposition is seen in those skin biopsy specimens taken from area of friction with sun exposure, which suggests that sun exposure could be one of the predisposing factors for macular amyloidosis. Thus, these findings confirm that frictional melanosis is a variant of macular amyloidosis and histopathological examination will help in confirming the diagnosis.