What Causes Swelling of One Arm? Your Questions Answered

Noticing that one arm is bigger than the other could spark immediate concern. Most causes for one swollen arm can arise from trauma from an injury or repetitive strain. Other causes for left or right arm swelling include deep vein thrombosis, a bone infection, or cellulitis. Read below for more information on other causes and how to treat unilateral arm swelling.

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Contents

  1. Symptoms
  2. Causes
  3. 8 Possible Swelling Of One Arm Conditions
  4. Treatments and Relief
  5. Real-Life Stories
  6. FAQs
  7. Questions Your Doctor May Ask
  8. Statistics
  9. Related Articles
  10. References

Swollen Arm Symptoms Explained

Since the arms are used for so many activities of daily life, it's unlikely any problems will go unnoticed. Swelling of one arm can interfere with your mobility and strength, particularly if other symptoms like pain are also present. There are multiple types of structures that drain fluid out of the arm: the venous system drains blood on its way back to the heart, and the lymphatic system drains cellular waste fluid. Blockage of the venous or lymphatic system in one arm can cause a backup of fluid, leading to swelling. Problems with the elbow joint can also cause swelling.

Common characteristics of swelling of one arm

Depending on the cause, arm swelling can be associated with the following additional symptoms:

What Causes Arm Swelling?

Swelling of one arm is typically caused by a local problem since systemic diseases associated with swelling will affect both arms and likely other parts of the body. Unilateral arm swelling can result from a problem with venous or lymphatic drainage; a local infection or inflammatory reaction; or an injury.

Venous problems

Problems in the veins can lead to swelling of one arm, such as the following.

  • Blood clot: A clot in one of the deep veins (deep vein thrombosis or DVT) of the arm can cause swelling, often accompanied by pain and redness. Arm clots are uncommon but can occur in the setting of vascular trauma, such as when a pacemaker or catheter is present [1]. A clot may be complicated by chronic arm swelling [2].
  • Compression: Compression of the large subclavian vein near the neck can obstruct venous drainage, leading to swelling and blue discoloration of the arm. Tingling in the fingers is often present due to hand swelling and/or nerve compression [3]. Anatomic abnormalities such as an extra rib are the primary cause. Subclavian vein compression is the primary cause of deep venous clots in the arm in the absence of catheters or other devices [2].

Lymphatic problems

Damage to the arm's lymphatic drainage system or mechanical blockage can cause a backup of lymph fluid (lymphedema). Tumors, lymph node surgeries, and certain infections can cause lymphedema and swelling in one arm [4,5]. Removal of lymph nodes in the armpit as part of breast cancer treatment is a particularly common cause of upper extremity lymphedema [6].

Inflammatory reaction

Inflammatory causes can lead to swelling of one arm, such as the following.

  • Vaccination: Rarely, swelling of the arm can be observed after receiving multiple doses of a childhood vaccine (DTaP) [7].
  • Insect bites: Most people will experience some degree of swelling with an insect bite on the arm. Those who have an allergy can have a larger amount of swelling, extending as much as 10 inches beyond the site of the bite [8].

Injury-related causes

Injuries can result in swelling of one arm in regards to the following.

  • Overuse injuries: Biceps tendonitis and acute injuries such as a fracture can cause swelling of the arm along with pain.
  • Chronic pain syndrome: An injury to the arm can be followed by a chronic pain syndrome characterized by pain, swelling, abnormal temperature sensation, and changes in the appearance of the skin [9].

Infection

An infection of the skin and deeper tissues of the arm will result in swelling, redness, and warmth.

8 Possible Swelling Of One Arm Conditions

The list below shows results from the use of our quiz by Buoy users who experienced swelling of one arm. This list does not constitute medical advice and may not accurately represent what you have.

Repetitive strain injury of the upper arm

Repetitive strain injury of the upper arm is caused by consistent repetitive use.

Rarity: Uncommon

Top Symptoms: upper arm pain from overuse, upper arm weakness, upper arm numbness

Symptoms that always occur with repetitive strain injury of the upper arm: upper arm pain from overuse

Symptoms that never occur with repetitive strain injury of the upper arm: upper arm injury, severe upper arm pain

Urgency: Self-treatment

Deep vein thrombosis

Deep vein thrombosis (DVT) is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh.

Rarity: Uncommon

Top Symptoms: fever, thigh pain, upper leg swelling, calf pain, butt pain

Urgency: Hospital emergency room

Cellulitis

Cellulitis is a bacterial infection of the deep layers of the skin. It can appear anywhere on the body but is most common on the feet, lower legs, and face.

The condition can develop if Staphylococcus bacteria enter broken skin through a cut, scrape, or existing skin infection such as impetigo or eczema.

Most susceptible are those with a weakened immune system, as from corticosteroids or chemotherapy, or with impaired circulation from diabetes or any vascular disease.

Symptoms arise somewhat gradually and include sore, reddened skin.

If not treated, the infection can become severe, form pus, and destroy the tissue around it. In rare cases, the infection can cause blood poisoning or meningitis.

Symptom of severe pain, fever, cold sweats, and fast heartbeat should be seen immediately by a medical provider.

Diagnosis is made through physical examination.

Treatment consists of antibiotics, keeping the wound clean, and sometimes surgery to remove any dead tissue. Cellulitis often recurs, so it is important to treat any underlying conditions and improve the immune system with rest and good nutrition.

Rarity: Uncommon

Top Symptoms: fever, chills, facial redness, swollen face, face pain

Symptoms that always occur with cellulitis: facial redness, area of skin redness

Urgency: Primary care doctor

Compartment syndrome

Acute compartment syndrome describes the damage done to certain muscle groups of the arms or legs after a traumatic injury.

All of the long muscles are bundled into sections – "compartments" – by the white sheets of strong, tough connective tissue called fascia. If something interferes with circulation so that blood flow is trapped within the compartment, pressure rises because the fascia cannot stretch. This causes serious damage to the muscles and other tissues within the compartment.

Acute compartment syndrome is caused by a broken bone; a crush injury; burns, due to scarred and tightened skin; and bandages or casts applied before an injury has stopped swelling.

Symptoms can rapidly intensify. They include severe pain and tightness in the muscle; tingling or burning sensation; and sometimes numbness and weakness.

Acute compartment syndrome is a medical emergency which can result in loss of the limb. Take the patient to the emergency room or call 9-1-1.

Diagnosis is made through patient history and physical examination.

Treatment involves hospitalization for emergency surgery and, in some cases, skin graft.

Rarity: Rare

Top Symptoms: arm numbness, hand numbness, foot numbness, pain in one leg, thigh numbness

Urgency: Hospital emergency room

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Bicep bruise

A bruise is the damage of the blood vessels that return blood to the heart (the capillaries and veins), which causes pooling of the blood. This explains the blue/purple color of most bruises. Bruises of the bicep are common due to minor injuries.

Rarity: Rare

Top Symptoms: constant upper arm pain, recent bicep injury, pain in one bicep, swelling of one arm, upper arm bruise

Symptoms that always occur with bicep bruise: recent bicep injury, constant upper arm pain

Urgency: Self-treatment

Bruised tricep

A bruise is the damage of the blood vessels that return blood to the heart (the capillaries and veins), which causes pooling of the blood. This explains the blue/purple color of most bruises. Bruises of the tricep are common, often due to minor injury.

Rarity: Rare

Top Symptoms: constant upper arm pain, tricep injury, pain in one tricep, swelling of one arm, upper arm bruise

Symptoms that always occur with bruised tricep: tricep injury, constant upper arm pain

Urgency: Self-treatment

Benign bony growth (osteochondroma)

An osteochondroma is a non-cancerous growth that usually develops during childhood or adolescence. It is a benign tumor that forms on the surface of a bone near the growth plate.

Rarity: Ultra rare

Top Symptoms: lower leg bump, upper leg bump, numbness in one thigh, painful thigh lump, hip bump

Urgency: Primary care doctor

Chronic upper arm bone infection (osteomyelitis)

Osteomyelitis of the upper arm is a bacterial or fungal infection of the bone, typically caused by Staph Aureus (40-50% of the time). It is difficult to diagnose as the infection can come from a break in the skin at the area or anywhere else in the body that spreads by blood.

Rarity: Rare

Top Symptoms: spontaneous shoulder pain, moderate fever, painful surgical site

Symptoms that always occur with chronic upper arm bone infection (osteomyelitis): spontaneous shoulder pain

Urgency: Hospital emergency room

Swollen Arm Prevention, At-Home Treatments, and Professional Treatments

The treatments for arm swelling vary since there are many different causes. Treatment options may also target associated pain. Understand your risk factors for certain conditions and possibly take the steps below to prevent them.

Prevention

There are methods of preventing swelling of one arm that can be coordinated between you and your medical provider.

  • Biopsy for cancer: Starting with a biopsy rather than lymph node removal for breast cancer staging and treatment leads to lower rates of arm lymphedema [10].
  • Avoid injected drug use: This behavior is a risk factor for clots and infections. If you do inject drugs, use clean needles and inject intravenously rather than into the skin or muscle, which will decrease the risk of infection.
  • Reduce clot risk: If you have any history of clots, avoid drugs containing estrogen, which will increase the risk of recurrent clots. Avoid smoking, which also contributes to clot risk.

At-home treatments

Some treatment methods for swelling of one arm can begin at home.

  • Pain medication: Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) are effective for pain associated with venous compression, injuries, and chronic pain syndrome.
  • Antihistamines: Benadryl, for example, will help alleviate the swelling and itching associated with insect bite reactions.
  • Rest and ice: Initial rest and icing followed by strengthening activities can help with overuse tendonitis [11].

Medical treatments

Medical treatments, such as the following, can be recommended after proper consultation with your physician.

  • Anticoagulation medication: This medication inhibits clot formation and is the best treatment for an arm clot. In some cases, a thrombolytic (medication to break up a clot already present) may also be used [2].
  • Surgery: This may be required to repair anatomic abnormalities causing venous compression or for tendon overuse injuries when other treatments have failed [11,12].
  • Antibiotics or drainage: An infection will require antibiotics and possibly drainage of infected fluid.
  • Massage and compression: Blocked lymphatic drainage can be partially improved with massage and compression, as well as addressing underlying causes like an infection or a tumor [4].
  • Other medications: Steroids and multiple types of pain medications, including antidepressants and antiepileptic drugs used for nerve pain, can help mitigate chronic pain syndromes [9].

When it is an emergency

You should seek care immediately if you experience the following.

  • Fever, drainage of a wound, and a spreading red or black/blue color of the skin
  • Shortness of breath and chest pain: This may indicate that a clot has dislodged from the arm and entered a lung (pulmonary embolism or PE).
  • Extreme pain and blue discoloration of the arm: This may indicate venous backup so severe that arterial blood flow is also blocked [1,2].

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FAQs About Swelling Of One Arm

Here are some frequently asked questions about swelling of one arm.

Can a swollen arm be a sign of infection?

Yes, a swollen arm may indicate an infection. Redness, warmth, and drainage may also occur. Some types of infection will cause blackened skin. Animal bites, intravenous drug use, and other types of injuries that break the skin are risk factors for infection. Seek emergency care if you have rapidly spreading skin changes or signs of systemic illness such as fever [13,14].

Why does one of my arms swell after activity?

Swelling after activity, particularly a repetitive activity like throwing, can be a sign of venous compression by an abnormality such as an extra rib. You may also notice pain and/or a red or blue appearance of the arm. It is important to receive medical attention if you notice swelling and other changes in your arm after activity since a clot can occur as a complication of venous compression [1-3,12,15].

Why do I have swelling of just one arm?

Many systemic medical conditions can cause swelling of both arms and/or legs while swelling of just one arm indicates a problem on that side. The swelling may be due to infection, particularly if it is localized to one area. It can also be caused by an acute or chronic injury. In addition, a structural abnormality of just one arm can cause swelling if it limits fluid drainage, either in the veins or in the lymphatic system [1,4,13,15].

What treatments are available for a chronically swollen arm?

Arm swelling that persists over time is often caused by a problem with venous or lymphatic drainage. Compression can help reduce swelling in both of these conditions. Additional treatments like massage and exercise can also be effective for lymphatic blockage. Surgery can be required for chronic swelling, but other treatments are typically tried first [4,12,16].

How can I tell if an insect bite on my arm is infected?

An insect bite is often followed by a small amount of swelling along with itching and redness. Some people develop more extensive reactions at the site of the bite, with a larger area of swelling, redness, and warmth. These large reactions can appear similar to a skin infection. However, the large inflammatory response to a bite starts quickly and peaks in about half a day. If the bite is complicated by an infection, symptoms will worsen after a few days [17].

Questions Your Doctor May Ask About Swelling Of One Arm

To diagnose this condition, your doctor would likely ask the following questions:

  • Did you just suffer from a high impact injury (e.g., a fall, collision, accident or sports trauma)?
  • Any fever today or during the last week?
  • Does your calf feel very tense?
  • Have you suffered from a burn?

If you've answered yes to one or more of these questions

Please take a quiz to find out what might be causing your swelling of one arm. These questions are also covered.

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Swelling Of One Arm Symptom Checker Statistics

People who have experienced swelling of one arm have also experienced:

  • 11% Pain In One Arm
  • 7% Pain In The Upper Arm
  • 6% Pain In One Shoulder

People who have experienced swelling of one arm were most often matched with:

  • 54% Deep Vein Thrombosis
  • 36% Cellulitis
  • 9% Repetitive Strain Injury Of The Upper Arm

People who have experienced swelling of one arm had symptoms persist for:

  • 32% Less than a week
  • 26% Less than a day
  • 25% Over a month

Source: Aggregated and anonymized results from Buoy Assistant (a.k.a. the quiz).

Swelling Of One Arm Symptom Checker

Take a quiz to find out what might be causing your swelling of one arm

References

  1. Douketis JD. Deep Vein Thrombosis (DVT). Merck Manual Consumer Version. Updated March 2018. Merck Manual Consumer Version Link
  2. Mintz A, Levy MS. Upper Extremity Deep Vein Thrombosis. American College of Cardiology. Published November 16, 2017. ACC Link
  3. Goshima K. Overview of Thoracic Outlet Syndromes. UpToDate. Updated January 5, 2018. UpToDate Link
  4. Douketis JD. Lymphedema. Merck Manual Professional Version. Updated September 2017. Merck Manual Professional Version Link
  5. Zakaria S, Johnson R, Pockaj BA, Degnim AC. Breast Cancer Presenting As Unilateral Arm Edema. Journal of General Internal Medicine. 2007;22(5):675-676. NCBI Link
  6. Mehrara B. Clinical Features and Diagnosis of Peripheral Lymphedema. UpToDate. Updated February 21, 2018. UpToDate Link
  7. Rennels MB, Deloria MA, Pichichero ME, et al. Extensive Swelling After Booster Doses of Acellular Pertussis Tetanus-Diphtheria Vaccines. Pediatrics. 2000;105(1):online. Pediatrics Link
  8. Golden DBK. Stinging Insect Allergy. American Family Physician. 2003;67(12):2541-2546. AAFP Link
  9. Complex Regional Pain Syndrome Fact Sheet. National Institute of Neurological Disorders and Stroke. Updated July 6, 2018. NINDS Link
  10. Purushotham AD, Upponi S, Klevesath MB, et al. Morbidity After Sentinel Lymph Node Biopsy in Primary Breast Cancer: Results From a Randomized Controlled Trial. Journal of Clinical Oncology. 2005;23(19):4312-4321. ASOC Journal Link
  11. Wilson JJ, Best TM. Common Overuse Tendon Problems: A Review and Recommendations for Treatment. American Family Physician. 2005;72(5):811-818. AAFP Link
  12. Rubin M. Thoracic Outlet Compression Syndromes (TOS). Merck Manual Professional Version. Updated July 2018. Merck Manual Professional Version Link
  13. Spelman D, Baddour LM. Cellulitis and Skin Abscess: Clinical Manifestations and Diagnosis. UpToDate. Updated August 14, 2018. UpToDate Link
  14. Cellulitis. Johns Hopkins Medicine. Johns Hopkins Medicine Link
  15. Young C. Throwing Injuries of the Upper Extremity: Clinical Presentation and Diagnostic Approach. UpToDate. Updated April 18, 2018. UpToDate Link
  16. Douketis JD. Chronic Venous Insufficiency and Postphlebitic Syndrome. Merck Manual Professional Version. Updated March 2018. Merck Manual Professional Version Link
  17. Kelso JM. Large Local Reactions to Mosquito Bites. UpToDate. Updated August 29, 2017. UpToDate Link
  18. Schutzman S. Evaluation of the Immobile Arm in Children. UpToDate. Updated February 12, 2018. UpToDate Link
  19. Berube C, Zehnder JL. Catheter-Related Upper Extremity Venous Thrombosis. UpToDate. Updated September 27, 2018. UpToDate Link
  20. Trayes KP, Studdiford JS, Pickle S, Tully AS. Edema: Diagnosis and Management. American Family Physician. 2013;88(2):102-110. AAFP Link

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