Answer:
This condition is called a splinter hemorrhage because it may look like a wood splinter under your nail. The condition is caused by damaged small blood vessels underneath your nail. Characteristics include the following: It's black or reddish brown in color.
There are a couple of risk lowering drugs you can take such as tamoxifen or raloxifene, or you can have a prophylactic mastectomy or a prophylactic oophorectomy.
