What causes a blue or black bruise

A bruise develops under the skin if locally a fall or impact has caused too much pressure. Very small blood vessels rupture resulting in blood leakage under the skin. The skin will show a discoloration as a blue, purple or black bruise. Normally these stains will recover within two to four weeks whilst the color changes. Bumps or bruises which occur lower of the body will recover more slowly as the blood pressure is relative higher. How are bruises caused? 


Many gradations

Most blue bruises are caused without pain and restore spontaneously. Often we don’t even know why or when we got the bruise as we don’t remember that we bumped into something. Many times we are distracted by other aspects of life so we don’t realize that we have hurt ourselves. If there is a serious impact or fall then it will swell and result in pain. If the swelling and pain starts within half an hour after the mishap than there might be a serious sprain or fracture.


Getting it quickly

Some people can get bruises very quickly and most likely don’t remember it happening. If you get it quickly then it doesn't mean you have a health problem. Especially elderly can get a bruise more rapid mostly on the head, hands and feet. This is due to the high age whereby the skin gets thin and less flexible. Fats under the skin reduce and with that the resilience of the skin drops. These changes combined with the influence of sun radiation makes that small blood vessels can more easily rupture. Women are more quickly bruised then men. 


Abuse or domestic violence

Some bruises of bumps are not due to a fall or accident but are caused by abuse or domestic violence. In that case the pattern of bruises needs to be investigated. If it occurs within close proximity then it might be due to someone that had had a firm grip on the person. Also bruises on the back or near the eye can indicate abuse or domestic violence. If you see these conditions with an acquaintance you should try to seek help for her or him. 


Bloodstain due to purpura

The forming of bloodstain in the skin can be cause by purpura or petechiae. Petechiae are harmless small discolorations up to three millimeters in size. Purpuras on the other hand are caused by more serious bleedings. The skin colors red or purple and the stains are up to a centimeter in size. These can occur in near proximity of one and another so it looks like a big portion of the skin is affected with it. When it concerns ecchymosis the stains are even bigger. This condition can by caused by typhus or meningitis. If you have several close clustered red or purple skin stains you should be examined medically.


Blue or black wound above the ankle

If the skin above the ankle turns blue, red, brown or dark then you should give it proper attention. This isn't caused by a fall or accident but is caused within the body itself. The condition is called deep vein thrombosis whereby blood flows more slowly than normal through the vessels. Veins in the legs are weak and will expand resulting in leaking valves and slow flowing blood. Red blood cells can escape from the vessel and leak into the skin where it accumulates. The skin changes color from red to brown or black. This skin is very fragile for wounds which recover very badly. Treatment will take several months.


Unexplained stains

If you get blood stains with no cause under the skin it can be caused by a bump due to alcohol abuse, infection, thrombosis, liver disease, cancer, leukemia, vascular disease, shortage of vitamins or minerals and bad food. If you frequently have unexplained blood stains you should get medical examination to rule out a life threatening situation.