Asked for female, 33 years old from Hyderabad
Black spots on skin can be caused by diabetes, plantar warts and foot melanoma, plantar warts on the feet may contain little black dots due to blood vessels growing within the warts.
The first warning sign of foot melanoma is a change in the color of moles on the foot. Most areas show blue or blue-black areas where melanoma is present.
Foot melanomas are also irregular, abnormal and swollen areas of the foot that may not heal right away. This type of black spot may denote skin cancer.
You may need an immediate examination if its in severe condition.