Deep vein thrombosis in the arms is rare, but it can happen. It may be more likely if you have had surgery or trauma to a vein.

When you get a cut, components of your blood coagulate, or clot, to stop the bleeding. But sometimes, blood in your veins or arteries can form a clot that serves no purpose, which can be harmful.

Three types of blood clots include:

  • Deep vein thrombosis (DVT): DVT occurs when a clot forms in a vein deep in your body.
  • Superficial thrombophlebitis: Superficial thrombophlebitis occurs when a clot forms in a vein near the skin’s surface.
  • Emboli: Emboli are clots that dislodge and travel to other locations in the body.

DVT usually occurs in the legs but can develop in the arms, too. This is called DVT of the upper extremities (DVT-UE). Of all DVT cases, 11% to 14% are DVT-UE.

As many as 33% to 60% of people with a blood clot in a deep arm vein may not experience symptoms. Symptoms may also gradually appear.

If you have a blood clot in your arm, symptoms in the affected arm may include:

  • swelling
  • cramping
  • tenderness
  • red or blue skin discoloration
  • skin that’s warm to the touch
  • weakness, though this may be rare

If you believe you may have a blood clot in your arm or another location, seek immediate medical attention.

Early signs of a blood clot can include:

  • arm swelling
  • pain, tenderness, or cramping not caused by an injury
  • skin discoloration with dilated (enlarged) veins
  • fluid retention
  • skin that’s warm to the touch
  • weakness or paralysis in the affected arm, though this may be rare
  • a higher than typical body temperature, though this may be rare

Blood clots form when various proteins and blood cells called platelets cause your blood to coagulate. There are two types of DVT-UE: primary and secondary.

Primary DVT-UE

Primary DVT-UE is rare. It refers to DVT not caused by trauma to the veins, surgery, immobility, or surgery.

It can occur without an obvious cause or from repeated, strenuous arm activity (sometimes called effort thrombosis, or Paget-Schroetter syndrome). People with effort thrombosis develop a clot — usually in their dominant arm — after a strenuous activity like rowing, wrestling, weightlifting, or baseball pitching.

Secondary DVT-UE

Secondary DVT-UE makes up 80% of cases. This occurs when something disrupts the vein, thus initiating the clot. Such disruptions can include:

  • surgery
  • trauma
  • central venous catheters
  • pacemakers
  • tumors
  • immobility, such as during bed rest or general anesthesia
  • pregnancy
  • vein stenosis, or narrowing
  • dehydration
  • thrombocytosis, or when the body produces too many platelets
  • anatomic variations in the veins

People who have certain types of medical implants are at an increased risk. These can cause damage to the veins. More than half of people with DVT-UE have a cardiac pacemaker or central venous catheter in the clot area, according to a 2017 review of research. The risk can depend on the type of device, its diameter, and its position. Infection can also increase the risk.

Cancer is the second most frequent risk factor. According to the same review of research, one study found that up to 49% of people with DVT-UE have a tumor.

Surgery can also increase the risk of blood clots. The same review of research noted that as many as 27% of people with DVT-UE developed a blood clot after an operation.

Other factors that can increase your risk of a blood clot can include:

  • being over 40 years old
  • having a sedentary lifestyle
  • smoking
  • having a history of other blood clots
  • taking certain medications
  • injuring a vein
  • having certain medical conditions, such as heart or lung disease

If you’ve had surgery or have a central line or pacemaker, your healthcare team may watch for blood clot signs so they can quickly diagnose and treat you. If you notice any blood clot symptoms, make an appointment with a doctor.

A doctor may conduct a physical exam and ask when the symptoms started, what you were doing before they started, and any other symptoms you may have. They will also likely have you take an imaging test.

An ultrasound is a fast, easy, and cost-effective way to look for a blood clot. During an ultrasound, sound waves penetrate your skin and create a view of your veins.

Other imaging tests a doctor may use to diagnose you or guide your treatment can include:

  • CT scan: This imaging test uses computers and X-rays to take cross-sectional images of your body to identify blood clots.
  • MRI scan: An MRI uses radio waves and magnets to take images of your body, including your veins.
  • Contrast venography: For this procedure, a doctor or specialist will inject you with a contrast dye and use an X-ray to see your veins.

Blood clots in the arm are serious, and you should immediately see a doctor if you suspect you have one. Anyone can develop a blood clot, though certain medical treatments and conditions may put you at an increased risk.

Blood clots are typically treatable if caught early.

The most serious complication of a blood clot is a pulmonary embolism, which is when part of the clot travels through the bloodstream and forms a blockage in the lungs. This can prevent blood from reaching your lungs, which can be fatal.

If you develop a deep vein clot in your arm, the primary treatment goals include:

  • stopping the clot’s growth
  • relieving your symptoms
  • preventing the clot from moving to your lungs or other parts of your body

Treatment can include:

  • Limb elevation: This reduces swelling and eases pain.
  • Graduated compression arm sleeve: This tight sleeve helps increase blood flow from the hand back toward the heart.
  • Blood-thinning medications: These medications help slow the formation of new clots and prevent existing clots from growing.

If these treatments don’t work or your clot is very large, a doctor may recommend removing the clot through surgery or by injecting medication into the vein.

Once you complete the initial treatment, you’ll likely continue maintenance therapy. This can last a minimum of 3 to 6 months, depending on the situation. Taking blood thinners and wearing your compression sleeve may help prevent your existing clot from growing and new clots from forming.

The most dangerous complication of DVT-UE is a pulmonary embolism, which is when part of the clot breaks off and travels to your lungs. This is a medical emergency.

Pulmonary embolism

If you experience sudden shortness of breath and a sharp, stabbing pain in your chest, seek immediate medical attention or call 911 or your local emergency services.

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Another possible complication is post-thrombotic syndrome, which may occur if the valves inside the clotted vein are damaged and cause high blood pressure in that vein. Symptoms vary but may include:

  • mild fluid retention
  • discomfort
  • debilitating limb swelling
  • pain
  • skin ulcers

Following your treatment plan — including taking medications and wearing compression sleeves — can prevent or limit post-thrombotic syndrome.

If you stick with your treatment plan, your overall outlook after a blood clot in your arm is good.

But blood clots can recur, especially if you need to keep a central venous catheter for ongoing treatments. If you experience any unusual symptoms, consult with a doctor.

There are several steps you can take to prevent blood clots from forming in your arms:

  • Ask a doctor if you’ll need blood thinners or compression garments during an extended hospital stay.
  • Ask a doctor how to prevent blood clots if you have a pacemaker or central venous catheter.
  • Exercise regularly.
  • Maintain a moderate weight.
  • Don’t sit still for too long. Move your feet, ankles, hands, wrists, and arms to keep your blood flowing.
  • Get regular checkups to look for and treat heart disease, diabetes, and cancer.

Blood clots can happen to anyone, though certain medical treatments and medical conditions can increase your risk.

Blood clots can cause a pulmonary embolism if left untreated, but they are typically treatable if you catch them early. If you experience signs of a blood clot, seek immediate medical attention.