When You Are Not Washing Your Hand Properly

A man from the China went to the hospital for a medical treatment after finding his hands suddenly turned black. 

When he was searching the information online, he thought he got a blood clot. The doctor on duty asked him if he was feeling uncomfortable and found that his hands were black. The doctor is surprised when he saw his hands were not swollen and painful, and his finger skin on the other sides was normal too.  

After a few minutes of medical check, the doctor didn't think it was a blood clot. In the end, the doctor checked many times and found that the blackening of the man's hand was caused by the discoloration of the pants. He was asked to wash his hands twice, and his skin will return to normal after washing.