Dermoscopy aids in differentiating primary cutaneous amyloidosis and post-inflammatory hyperpigmentation: A...

Primary cutaneous amyloidosis (PCA) and post-inflammatory hyperpigmentation (PIH) are common causes of cutaneous hyperpigmentation that are usually diagnosed clinically. However, their presentations are sometimes atypical, and their differentiation is difficult. Dermoscopy is a valuable diagnostic tool for pigmented diseases that might aid in their diagnosis.

To describe the characteristic dermoscopic features of PCA and PIH together with histopathological correlation, and to differentiate between these conditions in a non-invasive way.

Fifty-two patients with PCA (n = 26) and PIH (n = 26) were enrolled. A detailed history, skin examination, dermoscopic examination using handheld and video dermoscopy, and histopathological evaluation were performed.

A statistically significant difference could be detected between PCA and PIH in terms of the duration of the disease (p = 0.027), symmetry (p = 0.044), rippling (p < 0.001), and back affection (p = 0.048). On dermoscopic examination, central hubs were seen more in the PCA group (p < 0.001) with different patterns of peripheral pigmentation. Histopathologically, the number of melanophages per high-power field was significantly higher in the PCA group (p = 0.013).

The results of this study shed the light on the potential of dermoscopy as a non-invasive diagnostic tool in differentiating between doubtful cases of PCA and PIH.