Most commonly, a swollen forearm can be caused by insect bite or exposure to certain plants. Forearm swelling with pain can be caused by trauma from an injury. Read below for more information on causes and treatment options.
Swollen forearm symptoms
Whether your sleeve feels more snug than usual, or you can see that one of your forearms looks a bit puffy, forearm swelling can be a cause for concern. Swelling occurs whenever the parts of the body enlarge due to an accumulation of fluid in the body tissues. Swelling can be generalized and occur throughout the body, or localized and only affect a specific part of the body, such as the forearm.
Common characteristics of a swollen forearm
Localized swelling is more common, and in the case of a swollen forearm, the swelling may be difficult to ignore. Swelling in the forearm can be associated with:
- Generalized pain in the affected area
- Sensitivity to touch
- Redness or warmth
- Swelling in adjacent structures such as the hand
- Pitting: Skin that dimples or dents after pressing on the affected area for a few seconds
- Stiffness or limited range of motion
- Cramping or soreness
- A feeling of heaviness or tightness
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Swollen forearm causes
Even though the forearm has multiple components, forearm swelling is usually the result of damage or inflammation to the muscles and bones.
The bones of the forearm include the radius, which starts at the elbow and connects at the wrist on the thumb side, and the ulna, which starts at the elbow and connects at the wrist on the pinkie side. See this image for a visual representation. The forearm contains multiple muscles that turn the forearm/hand upwards (supination) and downwards (pronation) but and also flex and extend the digits of the hand.
Traumatic causes of a swollen forearm may include the following.
- Fracture: Anything that causes direct injury to the forearm, such as a car accident, a traumatic fall, a direct blow, can result in broken bones in the forearm, resulting in swelling and pain. These causes may also be associated with visible deformity and bleeding depending on the severity of the trauma.
- Sprain: A sprain is defined as twisting or stretching of a ligament or tendon. A ligament is a band of connective tissue that connects bone to bone. A tendon is also a band of connective tissue, but it connects muscle to bone. The forearm has multiple ligaments that can be sprained in activities that cause bending, twisting, sudden movement or direct impact.
A bite from an insect, such as a mosquito, spider, etc., can cause the forearm to swell and also become itchy and painful.
Cancers can specifically target the bones of the forearm. The body's lymphatic system (the system that filters excess fluid and fights infection) can become blocked, causing fluid to build up. This phenomenon is known as lymphedema and often affects the arms or legs.
This list does not constitute medical advice and may not accurately represent what you have.
Insect bite on the arm
Insect bites are a common occurrence. Despite the discomfort they cause, most bites are harmless and will resolve on their own.
Top Symptoms: swollen forearm, mild forearm pain, forearm bump, forearm redness, forearm itch
Symptoms that never occur with insect bite on the arm: fever, worsening forearm redness, severe forearm pain, high-pitched breathing, wheezing, racing heart beat
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.
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
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 forearm are common, often due to minor injuries.
Top Symptoms: constant forearm pain, pain in one forearm, forearm pain from an injury, forearm bruise, swelling of one forearm
Symptoms that always occur with bruised forearm: forearm pain from an injury, constant forearm pain
Buckle fracture of distal radius
A buckle fracture of the wrist, also known as a torus fracture, is a condition that are most common in children aged 5-10 years due to the elasticity of their bones. This fracture occurs when force is applied to the radius (one of the two bones of the forearm), causing the bone to split along the growth plate.
Top Symptoms: constant forearm pain, forearm pain from an injury, pain in one forearm, swollen forearm, wrist injury
Symptoms that always occur with buckle fracture of distal radius:forearm pain from an injury, constant forearm pain
Urgency: Primary care doctor
Acute forearm bone infection (osteomyelitis)
Osteomyelitis of the forearm 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.
Top Symptoms: moderate fever, spontaneous forearm pain, constant forearm pain, warm and red forearm swelling, painful surgical site
Symptoms that always occur with acute forearm bone infection (osteomyelitis): spontaneous forearm pain, constant forearm pain
Urgency: Hospital emergency room
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Swollen forearm treatments and relief
If your symptoms are due to a traumatic cause, promptly make an appointment with your physician in order to assess for serious injury. In the meantime, use the RICE method to help alleviate your symptoms.
- Rest: Limit movement and use of the affected forearm as much as possible.
- Ice: Put an ice pack on your forearm every 15 minutes in order to reduce swelling.
- Compression: Protect your forearm from excessive movement by using a compression wrap or tape. Compression can also help reduce swelling.
- Elevation: Raising your forearm above your heart can also help reduce swelling.
If your forearm swelling is due to trauma or malignant causes, your physician may suggest:
- Immobilization (sling): After a traumatic injury, your physician may provide a sling to keep your forearm from moving.
- Physical therapy or rehabilitation: Your physician may prescribe stretching exercises or a physical therapy program to help you restore function to your forearm, especially after an injury.
- Chemotherapy or radiation: If your symptoms are due to malignant disease, your physician will discuss options such as surgery, radiation, or chemotherapy with you depending on the specifics of your condition.
Questions your doctor may ask about swollen forearm
- Any fever today or during the last week?
- Is your swollen area warm and red?
- Do you notice your heart beating hard, rapidly, or irregularly (also called palpitations)?
- How would you explain your forearm pain?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
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- Faibisoff B, Daniel RK. Management of Severe Forearm Injuries. Surgical Clinics of North America. 1981;61(2):287-301. NCBI Link
- Forearm Fractures in Children. American Academy of Orthopaedic Surgeons: OrthoInfo. Updated October 2014. OrthoInfo Link
- Forearm Muscle Strain. Winchester Hospital. Winchester Hospital Link