Skin diseases: 

Our skin is the biggest organ of the body. It serves various functions like temperature regulation, protection from external elements and the production of vitamin D.
However, the exposure to harsh external factors and other causes, makes the skin vulnerable to several diseases. We have thousands of skin diseases, and many can look very different on people with different skin colours.
Fortunately, most of the abnormalities on the skin are visible and once identified, they can be addressed by certain treatments. Whilst blood tests are rarely useful, some of the skin diseases may need biopsies for confirmation.