Blood clots can form in veins throughout the body, including those in the arm. These clots can be dangerous if they dislodge and travel to other parts of the body, so swift treatment is essential.

The body forms blood clots in response to a cut, scrape, or injury. If a person sustains an open wound, platelets within the blood form a plug to stop the bleeding. When this occurs at the site of a wound, it is beneficial. However, when a clot occurs in the veins, it can be harmful.

In this article, we take a look at what happens when a blood clot forms in the arm, the potential causes, and the treatment options.

What is a blood clot?

Blood clot in arm
A blood clot typically forms to stop a cut from bleeding.

A blood clot is a semisolid clump of blood that typically forms to stop a cut from bleeding. At times, a blood clot may form within a vein.

Doctors describe and define blood clots according to where they form in the body. There are three types of clot:

  • superficial thrombophlebitis — a clot that forms in a vein near the surface of the skin
  • deep vein thrombosis (DVT) — a clot that forms in a vein deep within the body
  • embolus — a clot that moves from one part of the body to another

Clots that form in the deep veins in the arms are a form of DVT. According to one review of studies, about 4% to 10% of all DVT occurs in the arms.

DVT affects about one in 1,000 people per year. The majority of cases occur in a person’s legs.

Symptoms of a blood clot in the arm

Many people will not experience any symptoms when a DVT forms in their arm. In other cases, symptoms may develop slowly.

When they occur, the symptoms of a blood clot in the arm may include:

  • skin that is warm to the touch
  • pain that feels like cramping
  • swelling in the arm where the clot is
  • a red or blue hue to the skin
  • tenderness

If these symptoms occur, a person should seek emergency medical attention. DVT in the arms can be very dangerous.

Is it dangerous?

Blood clot in arm high blood pressure
A person may have raised blood pressure as the result of a blood clot.

Some of the possible complications of a blood clot in the arm can be dangerous.

One of the biggest dangers is that the clot could dislodge and travel to the lungs. If this occurs, it is called a pulmonary embolism. It can block the flow of blood to part of the lungs, causing that area of tissue to die.

A pulmonary embolism can be fatal, so it is vital to take it seriously. If a person experiences pain in the chest along with sudden shortness of breath, they may have a pulmonary embolism.

In addition, a person may have:

  • pain and swelling in the arm
  • raised blood pressure
  • partial blockage of the superior vena cava vein

When to see a doctor

A person should seek emergency medical assistance if they experience any of the symptoms of either a blot clot in the arms or a pulmonary embolism.

A doctor can diagnose the blood clot and provide appropriate treatment to help prevent further complications.

Causes

When a blood clot forms in the arm, doctors classify it as either primary or secondary. They base these designations on the cause of the clot.

Primary clots

Primary clots are rare compared with secondary clots. One known cause is Paget-Schroetter syndrome, which typically occurs following a strenuous activity that uses the arm, such as rowing.

Muscle overgrowth, bone growth, and bone fractures can also cause primary clots. Sometimes, the cause of a primary clot will be unknown.

Secondary clots

Secondary clots are much more common and contribute to 80% of all DVT cases.

Secondary clots occur when an event triggers the clot. Some events that can have this effect include:

  • the insertion of a pacemaker
  • tumor growth
  • the insertion of a venous catheter

Risk factors

The implantation of a medical device in the arm can put people at increased risk of developing a blood clot in this part of the body. The increased use of both catheters in the veins and pacemakers has led to an increased number of cases of DVT in the arms.

Cancer is another common risk factor for developing DVT in one of the arms. Having surgery also increases a person’s risk of developing a blood clot in this part of the body.

Some other factors that increase a person’s risk of developing a blood clot in their arm include:

Diagnosis

blood clot in arm ultrasound
Healthcare professionals commonly use ultrasound scans to examine potential blood clots.

Diagnosis typically begins with a physical examination of the area where the person is experiencing symptoms.

While a doctor examines the area, they are likely to ask questions about when the symptoms started, what was happening before they started, and any other symptoms that the person is experiencing.

If the doctor suspects that a blood clot is present, they will often order imaging scans. One of the most commonly requested scans is an ultrasound. The doctor may also order one of the following:

If a person is in the hospital following pacemaker surgery or another procedure, the healthcare team will monitor the person for signs of a blood clot. They will know the signs and symptoms of a blood clot as well as how to treat one if it forms.

Treatment

Treatment typically starts with the doctor making a plan of action. In most treatment plans, the goals are to:

  • stop the growth of the clot
  • prevent the clot from moving to other parts of the body
  • relieve symptoms, such as pain and swelling

Typical methods to treat a blood clot in the arm include:

  • elevation to help reduce swelling and pain
  • blood thinners
  • a graduated compression arm sleeve to increase blood flow from the hand to the heart

When a clot does not respond to these treatments, a doctor may recommend the removal of the clot. They can remove the clot by using a minor surgical procedure or injecting medication to break it up.

Over time, a person may have to continue to use blood thinners or compression. Doing this can help prevent another clot from forming in the arm. A person’s doctor will recommend a specified period of continued therapy, which tends to last for several months.

Summary

A person should seek medical attention immediately if they suspect that they may have a blood clot in the arm.

A blood clot in either of the arms can be dangerous as it might break loose and get into the lungs. If this occurs, it can cause a life-threatening situation.

A doctor can treat a blood clot in the arm with a few simple methods and therapies. Following treatment, a person can expect a few months of continued therapy to prevent further clots from forming.