Blood clots can form in veins throughout the body, including the arm. Signs to look out for include cramping pain, swelling, and skin that looks bruised and is warm to the touch. A clot needs urgent attention, as it can lead to complications.

The body forms blood clots in response to a cut, scrape, or injury.

These clots can be dangerous if they dislodge and travel to other parts of the body, so swift treatment is essential.

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.

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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 clots:

  • 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. About 5 to 10% of all DVT occurs in the arms, and incidences are rising annually.

It’s estimated that DVT affects roughly 900,000 people each year in the United States.

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.

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, and raised blood pressure, they may have a pulmonary embolism.

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.

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 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 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 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.

Below are some commonly asked questions about a blood clot in the arm.

What can be mistaken for a blood clot in the arm?

The following conditions can often be mistaken for a blood clot in the arm:

When should a person go to the ER for a blood clot in the arm?

If a person suspects they have a blood clot in their arm, they should go to the ER immediately.

It is possible for a blood clot to travel to the lungs, causing a pulmonary embolism. This can be life threatening and requires urgent treatment.

What are the five warning signs of a blood clot?

Here are some warning signs that a person has a blood clot in their leg or arm:

  • swelling, usually in one leg or arm
  • leg pain or tenderness (often described as a cramp)
  • reddish or bluish skin discoloration
  • leg or arm is warm to touch

What is the procedure for a blood clot in the arm?

Two procedures that are used to treat a blood clot in the arm are:

  1. Catheter-directed thrombolysis: This procedure involves a catheter being surgically inserted and directed toward the blood clot, where it delivers clot-dissolving medication.
  2. Thrombectomy: This is surgical removal of the blood clot.

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.