Petechiae are tiny red, purple, or brown spots on your skin, inside of your mouth, or on your eyelids. These sports develop when capillaries, small blood vessels, break and leak blood into your skin.

Hives, also known as urticaria, are raised, itchy welts on your skin that occur due to an allergen. The reaction is ...

Transfusions of red blood cells (RBCs) can be life-saving treatments for patients suffering from anemia, where the body lacks enough healthy RBCs to effectively deliver oxygen around the body. But the ...