Dermatoscopic evaluation and histopathological correlation of acquired dermal macular hyperpigmentation.

BACKGROUND: Acquired dermal macular hyperpigmentation (ADMH) is a hypernym encompassing Riehl's melanosis, lichen planus pigmentosus, and ashy dermatoses that show significant clinicopathological overlap. We sought to describe the dermatoscopic features of ADMH and correlate them with histopathological findings.

METHODS: This was a prospective observational study performed in two phases. A detailed clinical and dermatoscopic examination was performed, and skin biopsies were obtained in 51 patients. Two dermatologists and a blinded dermatopathologist studied archived dermatoscopic images and histopathology specimens, respectively.

RESULTS: Dermatoscopic features noted were (i) pigment structures; dots (82.4%), globules (66.7%) and blotches (56.9%) that spared the eccrine and hair follicle openings; (ii) telangiectasia (82.4%); (iii) accentuation of the normal pseudoreticular pigmentary network (33.3%); (iv) owl's eye structures (15.7%). Four dermatoscopic grades of disease severity were identified: grade 1 - dotted; grade 2 - Chinese letter; grade 3 - reticulate; and grade 4 - diffuse. Density of melanin incontinence on histopathology correlated positively with size of pigment structures (r = 0.7, P < 0.000) and grades of disease severity (r = 0.75, P < 0.000) on dermatoscopy.

CONCLUSION: Increasing grades of disease severity can be detected dermatoscopically, which correlate well with histopathological features. A carefully performed dermatoscopy aids in better patient counseling regarding disease severity.