DISCUSSION
There were two distinct characteristics from black palm in the present case. The clinical course was not indicative of black palm. The patient had a 5-year history of the black macule. The color of black palm varies within a short term and is dependent on the duration from the onset; dark-reddish on the 1st day, violaceous on the 2nd and 3rd day, bluish from the 4th to the 6th days, and dark green from the 7th to the 10th day 1. Furthermore, the clinical background did not suggest a diagnosis of black palm. The patient had not engaged in any sports associated with hard hand activities. In contrast, black palm commonly occurs in association with sports causing a lot of pressure on the hands, such as weight lifting or gymnastics 1.
The present case indicated that dermoscopy can show a single dermoscopic finding of hemorrhage crusts in solitary angiokeratoma. Dermatologists need to recognize this dermoscopic pitfall when examining hemorrhage crusts and carefully clarify the clinical course to prevent an underlying condition being overlooked.