Swollen lymph nodes in the forearm area are almost always located near the inner elbow, in a spot called the epitrochlear region. These small nodes filter fluid draining from your hand, wrist, and forearm, and they swell when something triggers an immune response in that drainage area. The most common cause is a nearby infection, but because epitrochlear nodes larger than 5 millimeters are always considered abnormal, any noticeable swelling here is worth paying attention to.
Where Forearm Lymph Nodes Are Located
You have a small cluster of lymph nodes on the inside of your arm, just above the elbow. These are the epitrochlear nodes, and they’re the only easily detectable lymph nodes between your armpit and your hand. Most people can’t feel them at all under normal circumstances. When they do swell, you’ll typically notice a small, sometimes tender lump on the inner side of your elbow crease.
Because these nodes specifically drain the hand, wrist, and forearm, swelling here usually points to a problem somewhere in that territory. Less commonly, it can be part of a body-wide process affecting lymph nodes in multiple locations at once.
Infections in the Hand or Forearm
The majority of epitrochlear swelling is reactive, meaning the node is responding to an infection or injury downstream. A cut on your hand that gets infected, a fungal nail infection, or cellulitis spreading up from a wound can all cause the node near your elbow to enlarge and become tender. Painful, swollen nodes are a hallmark of infection rather than something more serious.
Cat scratch disease is one of the more well-known causes. A scratch or bite from a cat on your hand, wrist, or lower forearm can introduce a bacterium called Bartonella henselae. Within a few weeks, the epitrochlear node swells, and you may develop small pustules on the wrist or forearm near the original scratch. The diagnosis is usually made based on the history of a cat scratch combined with blood tests, and it typically resolves on its own over several weeks.
Systemic and Autoimmune Conditions
Sometimes swollen epitrochlear nodes aren’t about a local injury at all. They can appear as part of a broader illness affecting the whole body. Historically, enlarged epitrochlear nodes were closely associated with secondary syphilis, and clinicians still check for them during syphilis evaluations. HIV infection is another systemic cause that can produce swelling in this area, often alongside enlarged nodes elsewhere in the body.
Sarcoidosis, a condition where clusters of inflammatory cells form in various organs, can also cause epitrochlear swelling. Rheumatoid arthritis occasionally triggers it too, particularly in people experiencing joint stiffness, swelling, and fatigue in the affected arm. These autoimmune and inflammatory causes account for a smaller proportion of cases, roughly 5% in some clinical series, but they’re worth considering if no obvious infection is present.
When Swelling Could Signal Something Serious
Epitrochlear nodes larger than 5 millimeters are always considered pathologically enlarged, and the two most concerning causes at that size are lymphoma and melanoma. That said, the characteristics of the node matter more than size alone. Nodes that feel hard, rubbery, fixed in place, and painless raise more concern for cancer or granulomatous disease. Nodes from a viral or bacterial infection, by contrast, tend to be mobile, soft, and tender to the touch.
Several features increase the likelihood that swollen lymph nodes have a serious underlying cause:
- Duration beyond two weeks with no improvement or clear infectious cause
- Progressive growth over time rather than staying the same size or shrinking
- Hard, fixed texture that feels stuck to surrounding tissue
- No pain or tenderness, which paradoxically is more worrisome than a sore node
- Constitutional symptoms like unexplained weight loss exceeding 10% of your body weight, drenching night sweats, or persistent fevers
Swelling that lasts less than two weeks, or that has remained stable for over a year without growing, carries a very low probability of being cancerous.
What to Expect During Evaluation
If you notice a lump near your inner elbow, a doctor will typically examine your hand, wrist, and forearm for signs of infection, skin breaks, or rashes that could explain the swelling. They’ll feel the node itself to assess its size, texture, and mobility, and check whether lymph nodes in other areas (neck, armpits, groin) are also enlarged.
When the clinical picture looks benign, a three- to four-week observation period is standard. Many reactive nodes shrink on their own once the triggering infection clears. If the node persists beyond that window, continues to grow, or you’re experiencing constitutional symptoms like weight loss or night sweats, a biopsy is the next step to rule out lymphoma or other serious causes.
For suspected cat scratch disease, blood tests checking for antibodies to the causative bacterium can confirm the diagnosis. Syphilis and HIV are screened with their own blood tests. If an autoimmune condition like rheumatoid arthritis or sarcoidosis is suspected, additional bloodwork and imaging help narrow things down.
Common Causes at a Glance
- Local infections: Cuts, cellulitis, fungal infections, or abscesses in the hand or forearm
- Cat scratch disease: Bacterial infection from a cat scratch or bite on the hand or wrist
- Secondary syphilis: A sexually transmitted infection that can enlarge epitrochlear nodes bilaterally
- HIV: Generalized lymph node swelling that often includes the epitrochlear area
- Sarcoidosis: Inflammatory condition producing granulomas in lymph nodes and other organs
- Rheumatoid arthritis: Autoimmune joint disease that occasionally triggers nearby node swelling
- Lymphoma or melanoma: Less common but the most important to rule out when nodes are hard, painless, and persistent