Bruises without a reason: what is behind them?

Bruises often result from a blunt impact, such as a bump, hit, or fall. As a result, blue to purple spots form, which can also be associated with pain or swelling. But what if bruises suddenly appear for no reason? Anyone who suddenly notices a bruise on their arm, hand or leg and cannot remember the reason often suspects an illness to be the cause. Bruises that appear for no reason can be a sign of a disease. A coronavirus infection may also be behind it. We present possible causes of bruises.

Bruises for no reason – common causes

When a blood vessel is injured near the surface of the skin and blood leaks into the surrounding tissue, a bruise or bruise forms, medically known as a hematoma. In most cases, bruises are caused by external influences on the body, such as falling or being hit during sports or bumping into an object in everyday life. Bruises often form after a vaccination, a blood test or an operation because small blood vessels in the skin are injured.

Sometimes, you bump into yourself in everyday life without consciously noticing it – this can be the case, especially with stress, due to the increased adrenaline output. Or you don’t remember hitting yourself later and seeing a bruise afterwards, the cause of which you don’t know.

Therefore, a bruise without a reason is not immediately a cause for concern. Especially on the leg, arm or hand, bruises are often the result of unnoticed bumping.

 

Sudden bruises – other possible reasons

In addition to an unnoticed bump, other causes of sudden bruises are also possible:

• Medications: Blood-thinning medications, such as acetylsalicylic acid or heparin, can increase the risk of bruising. The anticoagulants weaken blood clotting, and the body takes longer to close wounds and stop bleeding. Bleeding, also in the form of a bruise, is a well-known side effect of anticoagulants. Cortisone and some antibiotics can also cause bruising all the time.
• Age: With age, blood vessel walls and skin thin. As a result, vessels can rupture more quickly in old age, and at the same time, the skin of older people increasingly loses its protective function. This is why older people often bruise faster than younger people. Children often have bruises, too, usually caused by romping or falling.
• Vitamin deficiency:  A lack of vitamin K can manifest itself, among other things, in increased bleeding after injuries, but also in the fact that you quickly get bruises,  nosebleeds or bleeding gums. Vitamin C is also essential for the blood vessels and connective tissue and should, therefore, be supplied to the body in sufficient quantities.
• Haemophilia:  People with haemophilia A (a bleeding disorder) quickly develop large bruises because the inherited disease prevents blood from clotting.
• Leukemia:  Leukemia can also cause skin changes and a tendency to bleed with increased bruising. However, other symptoms, such as fatigue, paleness or shortness of breath, often appear.
• Myelodysplastic syndrome (MDS):  This is a collective term for various diseases of the bone marrow in which blood formation is impaired, including that of the blood platelets. Therefore, bruising can occur more quickly.
• Thyroid disorders: Various thyroid disorders, particularly hypothyroidism, can result in a tendency to bruise.

If you bruise frequently for no apparent reason, seek medical advice to rule out a severe medical condition as the cause.

Bruises and skin changes caused by Corona

In rare cases, bruises can also occur as a symptom of a coronavirus infection. First, a doctor from Italy reported a 13-year-old boy who had contracted COVID-19 and had bruises on his feet. Based on this case report, other doctors who had made similar observations in young infected people came forward. Corona-related bruising, often frostbite-like lesions, and other skin changes on the toes have been named COVID-19.

In Italy, it was reported that skin lesions were visible in 18 out of 88 people with COVID-19. Some of those affected developed skin rashes (erythematous rash) on the trunk during the illness, and others developed skin rashes only later after discharge from the hospital. In addition to bruises, itchy blisters, hives or redness are now associated with Corona. Changes such as spots or inflammation were also found on the tongue, known as a COVID tongue.

In the meantime, such skin changes can be traced back to a reaction of the immune system: Antibodies inadvertently attack your skin cells. Bruises form due to the destruction of small blood vessels, usually on the toes or fingers.

Here is detailed information on recognizing the symptoms of coronavirus infection.

 

Corona: Bruises are not yet a proven symptom

The results of the case reports attracted a lot of attention, but they must be interpreted cautiously and do not allow general conclusions. The number of cases needs to be more significant for that. Scientific studies on the connections and the frequency of bruises as a corona symptom are still pending. However, it is believed that this is a reasonably rare symptom.

In addition, skin changes occur with many viral infections and do not necessarily indicate an infection with the coronavirus. It is also known from other viral diseases that infections can become visible on the skin.

Petechiae: small bruises

Petechiae are pinpoint haemorrhages that appear as a collection of numerous pinhead-sized red or blue dots on the skin. This is usually due to a blood clotting disorder.

In connection with the coronavirus vaccination, petechiae have been observed as a warning sign of thrombosis, which has occurred in rare cases after vaccination with Vaxzevria®, AstraZeneca’s corona vaccine. They can also be a symptom of serious illnesses. However, petechiae are usually harmless and – like bruises – are caused by mechanical effects on the skin, such as pressure or friction, or as a side effect of medication.

Treat bruises yourself: what helps?

You can quickly treat a more minor and harmless bruise yourself. It is best to immediately elevate the affected skin area and cool it with an ice pack you have previously wrapped in a kitchen towel to prevent cold-related skin injuries. Prompt cooling can often prevent the bruise from spreading because the blood vessels constrict due to the cold, and less blood reaches the tissues. Compression with an elastic bandage can also help.

If bruises have already formed, an ointment containing the active ingredient heparin can promote blood clotting and accelerate healing. Arnica ointments can reduce swelling and relieve pain.

Huge bruises, or those that spread quickly, require prompt medical attention. There is a risk of excessive blood loss, infection, or damage to surrounding tissues that the pool of blood is putting pressure on.