New Health Guide

What Causes Unexplained Bruises on the Legs?

Nov 23, 2017

Unexplained bruising generally causes alarm and most people want to know the "why" and if a serious problem is responsible. Bruises can appear anywhere on the body and their location can be a clue to the underlying cause. Many minor factors can result in bruising, but knowing when a serious cause is present can be life saving.

Bruises appear as skin discoloration and are blue, black or a combination of the two. Damaged blood vessels from deep within the legs cause blood to rise to the surface and causes unexplained bruising. Bruises generally heal within 2 to 4 weeks. When a bruise is healing, a variety of color changes take place and can produce a spectrum of colors from yellowish green, brown, reddish-blue and the common blue or blue-black appearance.

Causes of Unexplained Bruising on Legs

1. Physical Activity or Injuries

Seemingly minor injuries can result in bruising and contusions. It may take a few days for the blood to rise to the skin surface and this often causes concern about what was the actual cause. Strenuous physical activity can result in damage to small blood vessels. The blood then leaks out and a bruise forms.

2. Sun Exposure

The sun's UV radiation damages skin and blood vessels and results in bruising, particularly in elderly people.

3. Medication Side Effects

A variety of medications can affect the ability of blood to clot. The function of platelet blood cells is impaired by many anti-inflammatory medications. Aspirin and ibuprofen both affect platelet function. Other medications that cause inflammation in tissues and blood vessels can also result in leakage of blood causing bruising. Examples are birth -control bills and corticosteroids.

4. Aging

Tissues, particularly the connective tissues, weaken with age and even minor insignificant trauma can result in bruises appearing.

5. Vitamin Deficiency

Vitamins are cofactors in a variety of body processes and deficiencies in vitamins B12, C, K and folic acid can result in tissue or blood vessel weakness resulting in unexplained bruising on legs.

6. Reduced Body Fat

Body fat is the body's own natural cushioning system. Thin people or people on a quick weight loss plan are more prone to bruises for this reason.

7. Diabetes

Long-standing diabetes results in vascular disease and can cause easy bruising. Acanthosis nigricans is a dark bruise-like discoloration of the skin over body folds and around the neck. Many feel that the presence of this discoloration is a warning sign of impending diabetes developing.

8. Blood Disease

A variety of blood related diseases and conditions can cause excessive bruising. Examples include sepsis, thrombocytopenia, hemophilia, leukemia, Hodgkin's disease, and platelet dysfunction. Blood cancers can cause either an excess of deficiency of certain blood cells that function poorly and can result in excessive bruising, fatigue, weight loss and weakness. Any suspicion of these types of diseases requires prompt medical attention as they can be deadly.

9. Graves' Disease

An overactive thyroid causes global changes in the body's physiology. Persons with Graves' disease will lose weight, develop thin and easily bruised skin and loose hair. Further changes to the small capillary blood vessels in the skin result in easy bruising.

10. Other Medical Conditions

  • Sepsis is a serious infection and bruising can occur due to dysfunction of the clotting system.
  • Ehlers-Danlos syndrome is a connective tissue problem and bruising can be seen due to weakness of connective tissue.
  • Lupus is a chronic inflammatory disease that can cause bruising as well as joint pain.

Remedies for Unexplained Bruising on Legs

Home Remedies

  1. Cold Compress. Ice is helpful in a number of ways. The cold can constrict injured blood vessels stopping bleeding and helping limit inflammation. Try wrapping an ice bag in a towel and applying to the injured area or bruised area for 15 minutes three times a day.
  2. Warm Compress. After a bruise has been present for 48 hours, heat will help the bruise dissipate faster. Apply a warm towel or heating pad for 10 minutes three times a day to speed the re-absorption of the bruise.
  3. Elevating the Legs. Large bruises generally result in swelling and elevating the leg can help limit the bruising and minimize the swelling. This is especially important for contusions and bruises of the extremities.
  4. OTC Medications. Acetaminophen is the best choice for pain relief. Please avoid medications like aspirin and other OTC anti-inflammatories which can inhibit clotting and result in increased bruising.

Medical Treatments

There are not any special medical treatments to heal bruises any faster than supportive home care.

Call the doctor if:

  • Large unexplained bruises occur
  • You have bleeding gums
  • You are experiencing abnormally heavy menstrual periods
  • You experience massive swelling or extreme pain, especially if you are taking a blood-thinning type medication (ex: coumadin, pradaxa, lovenox)
  • If a bruise does not improve or resolve in two to three weeks

Preventions for Unexplained Bruising on Legs

This starts in the home. Keep extension cords away from walkways and secured. Don't place furniture in common walking paths or near doorways. Use protective padding when playing sports or working on your knees. Clean up spills immediately. Keep rugs secure to prevent slipping and falls. Use nightlights to illuminate a path to the bathroom or near stairs.