Causes: bruising is usually occurs after some type of trauma to the skin, causing discoloration and swelling. For frequent or chronic bruising, other causes should be ruled out, such as blood diseases such as leukemias, hemophilia, and multiple myeloma, kidney and liver disorders, or as side-effects to medications. 

Treatment:

Medical treatment is aimed at correcting any underlying problem that could have caused the bruising, such as the disorders above, or changing the offending medication. If the bruise is just due to trauma, use ice on the area initially for several days, then alternate between heat and cold. 

Alternative treatment for bruising and capillary fragility is aimed at increasing the intake of substances that strengthen the blood vessels. This includes vitamin C and flavonoids such as quercetin, hesperidin, rutin, and citrus bioflavanoids, as well as vitamin A. 

Reference:

Alt Med Rev 2003 Nov;8(4):359-77.