Bruises without a blow: what are the causes?

Doctissimo: Anne-Sophie Glover-Bondeau Health journalist

Published on 01/10/2012 at 00h00, updated on 10/09/2021 at 00h00

Medical validation: Jesus Cardenas, physician, former medical director

For some time now, you have noticed with concern that you have spontaneous bruises, without having been hit. What could be the causes of these spontaneous bruises? What tests will your doctor prescribe for you? Answers from Professor Stéphane Leprêtre, hematologist at the Henri Becquerel center in Rouen, and Dr Philippe Blanchemaison, Parisian phlebologist.

Summary

1 | Bruises without a blow: bruise or hematoma?

2 | Bruises without a hit: a drop in platelets is the cause

3 | Bruises without a hit: venous insufficiency the cause

In the face of spontaneous hematomas, it is first necessary to see if there is not a drop in the level of platelets in the blood. The other cause of spontaneous bruising is venous insufficiency

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Bruises without a blow: bruise or hematoma?

"A spontaneous bruise is a bruise that appears without a blow or after minimal trauma that should not have caused a bruise," explains Professor Stéphane Leprêtre.

Not to be confused with a hematoma which is a more significant hemorrhagic syndrome: "A hematoma is a pocket in which there is blood; it can be located, for example, at the level of certain joints", indicates the hematologist.

If you have small red-wine spots on your skin, it is purpura, infiltration of blood under the skin, due to a decrease or dysfunction of platelets, a blood disease or a dysfunction of the blood capillaries. "If these red spots are rather localized at the level of the legs, they can be linked to a fragility of the blood capillaries", specifies Professor Leprêtre.

Bruises without a hit: a drop in platelets in question

The platelet count is abnormal

"In the event of spontaneous bruising, your doctor will prescribe a blood test to check your platelet count," says Professor Leprêtre, because "the primary cause of spontaneous bruising is in fact a drop in the platelet count."

This thrombocytopenia or thrombopathia (decrease in the number of platelets in the blood) can have many causes.

• It can be peripheral, meaning that the platelets are destroyed outside the bone marrow. "Peripheral thrombocytopenia can be associated with an autoimmune disease or be drug-induced (aspirin, nonsteroidal anti-inflammatory drugs, antibiotics, etc.)". In the latter case, it is a functional disorder of the platelets that is not quantitative but qualitative.

• The decrease in platelets can also have a central origin. In this case, platelet production is reduced in the bone marrow. "All hematological diseases (leukemia, Hodgkin's disease, sickle cell disease, anemia, etc.) can cause central thrombocytopenia," says Professor Leprêtre.

What about treatment? "If there is thrombocytopenia or thrombopathia, this requires a consultation in hematology or internal medicine," says Professor Leprêtre.

The platelet count is normal

"If the platelet count is normal, it could be a hemostasis disorder," he adds. These can be primary (related to platelets) or secondary. Still by taking a blood test, we will look at the markers of secondary hemostasis:

• TP (prothrombin time)

• APTT (activated partial thromboplastin time).

  
  

"If the platelets are normal but the PT or APTT are abnormal, it could be a case of von Willebrand disease, hemophilia or a constitutional deficiency in hemostasis factors," says Professor Leprêtre. "These disorders tend to cause hematomas," he adds.

Bruises without a hit: venous insufficiency the cause

"When the doctor has ruled out a platelet problem, a venous problem must be considered, another cause of spontaneous bruising," says Dr. Philippe Blanchemaison.

"Many women get spontaneous bruises without hitting themselves because of poor venous return," he informs. The wall of the veins is then too fragile to support the weight of the blood when the woman is standing or sitting, the veins dilate, the pressure of the large veins resonates in the small vessels, which explains why the venules are more sensitive to the slightest blow," explains the phlebologist.

Spontaneous bruises in this case are a reflection of the fragility of the microcirculation

They are often accompanied by:

• Heavy leg sensations

• Swollen legs.

"If the veins are fragile, there may be bruises elsewhere than on the legs, for example on the hands," he explains.

What are the treatments?

This venous insufficiency can be treated by:

• Wearing support stockings or tights

• Taking veinotonics.

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