Leg Bruises (Red, Purple, Blue Patches on Legs) Causes, Treatment

Bruises on the skin appear as red to purple or blue patches that arise when there is bleeding under the skin. The presence of bruises after an injury is not unexpected. Some people do bruise more easily than others and this may not be considered abnormal. Similarly bruising may show more easily on some people, like those with pale skin complexions, and this is also not considered abnormal.

However, when bruises appear without any preceding trauma then it needs to be investigated by a medical professional. This is especially important if recurrent bruises appear for no clearly identifiable reason. Sometimes dark patches may form on the leg in conditions where there is poor circulation. However, this may be due to hyperpigmentation (increased skin pigment deposition) rather than due to bruising.

Meaning of Leg Bruises

Bruising on the leg means that the blood vessels at the affected area has ruptured and leaked blood into the tissue spaces. This is usually a result of trauma (injury). However, the presence of leg bruises without any identifiable trauma can be a sign of some underlying disease where the blood vessels are abnormally weak, rupture easily or the blood does not clot as it normally should.

Bruises may vary in size and shape from tiny spots to large patches. This may be known by various medical terms such as petechia, purpura or ecchymosis as explained under easy bruising. Minor breaks in blood vessels occur very frequently but a blood clot forms rapidly to prevent significant blood loss. With larger breaks clotting may not be able to prevent blood loss but can slow it down and eventually stop it, otherwise medical attention is necessary.

Causes of Bruising on the Legs

Visible skin bruising is due to the collection of blood in the tissue spaces just underneath the skin. Initially this appears red since this is the normal color of blood. As time passes the blood cells begin to break down and the color of the bruise changes from red to purple or blue. Eventually it may become brown to black in color.

Trauma

Injury to the leg is the most likely cause of the bruises. This can occur through various ways such as a fall, contact sports, blow to the leg or insect bite. Usually the trauma is identifiable and a bruise may set in after a few minutes or hours. It can take days and sometimes even weeks before it clears.

However, when severe bruising occurs with very little trauma or even after incidents that are not usually considered to be traumatic then it has to be investigated further. There may be an underlying disorder with the blood vessel or blood clotting that causes even slight force to rupture the blood vessel or lead to excessive bleeding.

Blood Clotting Disorders

There are various clotting chemicals in the bloodstream that are constantly circulating in an inactive form. When an injury to the blood vessel occurs then these chemicals known as clotting factors activate. It initiates the clotting mechanism to plug the break and stop any bleeding.

In conditions like hemophilia, von Willebrand’s disease and vitamin K deficiency, the blood clotting mechanism is either slow or severely impaired. There may also be disruption in blood clotting with leukemia, liver failure, severe infections and other types of blood disorders where thee is a problem with blood cell formation.

Blood Vessels Disorders

If a blood vessel is abnormally weakened or diseased then it may be unable to contain blood within it. Even very slight trauma can allow blood to leak out or it may seep out spontaneously. This is seen in conditions like Henoch-Schonlein purpura which is an autoimmune condition that leads to blood vessel inflammation.

A more common problem is varicose veins. Here the valves within the leg veins weaken and the blood cannot efficiently flow upwards towards the heart. The blood then pools in the legs and depending on the severity of the condition, the blood may seep out of the veins into the tissue spaces where it forms patches resembling bruises.

Substance Use

There are various substances that can affect blood clotting and thereby lead to bruising. This includes certain medication. Anti-clotting drugs are by far the most common, such as warfarin and even aspirin. Other drugs like corticosteroids and anti-cancer agents may also disrupt blood clotting mechanisms.

Other substances like alcohol can also affect blood clotting. It is more likely to occur with excessive alcohol consumption and especially in people who abuse alcohol for long periods of time. In the latter case this may be linked to liver disease as a result of alcoholism.

How to treat leg bruises?

It is important to differentiate between leg bruising that occurs from trauma and bruising that may be linked to underlying diseases. The latter needs to be treated medically in order for the severity and frequency of bruises to reduce. Never stop any prescribed medication due to the presence of leg bruises without first consulting with a medical professional.

Leg bruising can be treated, managed and prevented with the following measures:

• Apply ice to the area of injury for the first 24 to 48 hours to reduce inflammation. Heat can worsen bleeding under the skin if applied immediately after an injury.
• Elevate the legs when sitting or sleeping if varicose veins is a problem. Avoid prolonged standing as this allows the blood to further pool in the legs.
• Use compression stockings for varicose veins as advised by a doctor. These stockings apply external pressure to the vein and help the valves within it to function better.
• Use protective clothing like when playing contact sports to minimize the impact on the legs. It may not always be possible to prevent trauma but simple measures can help to reduce the extent of injuries in some instances.
• Ensure a balanced diet as some blood clotting disorders may be linked to nutritional deficiencies. Supplements may also be advisable in the event of a deficiency and should be used as prescribed by a medical doctor.

References

1. Bruises. WebMD.com
2. Contusions. Medscape

Last updated on September 7, 2018.