What are lymph nodes and why do they swell?
Part of the body's immune system, lymph nodes are small, bean-shaped glands that act as filters for foreign substances like viruses and bacteria. They are strategically located in clusters throughout the body, including the neck, armpits, and groin. When your body fights an infection, these nodes work overtime to trap and destroy harmful germs, causing them to swell. This swelling, known as lymphadenopathy, is often a healthy sign that your immune system is engaged in its job.
Common, benign causes of swollen lymph nodes
In the vast majority of cases, a swollen lymph node is a temporary and harmless reaction to an underlying infection. The location of the swelling can often offer a clue to the cause. For example, a cold or sore throat can cause swelling in the lymph nodes of the neck, while an infection in the arm can affect those in the armpit.
Common benign causes include:
- Upper respiratory infections: The common cold, flu, and strep throat.
- Ear infections: Can cause swelling in the nodes behind the ear or in the neck.
- Skin infections: Like cellulitis or a localized wound infection.
- Dental infections: An abscessed tooth or inflamed gums (gingivitis) can lead to swelling in the neck or under the chin.
- Mononucleosis: A viral illness that can cause widespread lymph node swelling, fever, and fatigue.
Performing a self-check for swollen lymph nodes
Being familiar with the location and feel of your lymph nodes can help you monitor any changes. It's important to be gentle and not press too hard, using your fingertips to feel for any lumps. Here’s how you can perform a self-examination:
- Neck: Gently run your fingertips along both sides of your neck, under your jaw, and behind your ears. Tilt your head toward the side you're checking to relax the muscles and feel more easily.
- Armpits: With your arm slightly raised, use your opposite hand to feel the central and outer areas of your armpit. Use a circular motion to feel for any distinct lumps.
- Groin: Feel along the crease where your thigh meets your torso, as well as the area along your upper thigh.
Remember to compare both sides of your body. Healthy lymph nodes are often too small to feel, but some people can feel them as soft, small bumps.
Knowing when to be concerned
While most swollen lymph nodes are not serious, certain signs may indicate a more significant issue like an infection that requires treatment or, in rare cases, cancer. A cancerous lymph node will typically feel different from one swollen due to an infection.
| Benign vs. Potentially Serious Swollen Lymph Nodes | Characteristic | Benign (Infection) | Potentially Serious (Malignancy) |
|---|---|---|---|
| Feeling/Texture | Soft, movable, and often tender or painful to the touch. | Hard, rubbery, or fixed in place (doesn't move when pushed). | |
| Pain | Often painful, especially during an active infection, as the node expands quickly. | Often painless, which can make it easier to overlook. | |
| Size | Typically less than 1.5 cm (pea to bean-sized) and may fluctuate in size. | Larger than 1.5-2 cm (grape or larger) and may continue to grow. | |
| Growth Rate | Appears suddenly and should recede within 2-4 weeks as the illness subsides. | May appear gradually and persist for more than 2-4 weeks, or continue to enlarge. | |
| Location | Often localized to an area near an infection (e.g., neck for a sore throat). | Swelling in multiple areas of the body, or in a supraclavicular node (above the collarbone), raises concern. |
Other lumps that might be mistaken for a swollen lymph node
Not every lump is a lymph node. There are other common, non-lymphatic causes for lumps, such as:
- Cysts: A fluid-filled sac that can form just under the skin. They are typically soft and movable.
- Lipoma: A harmless, soft, fatty tissue growth that moves easily when pressed.
- Abscess: A painful, localized collection of pus caused by an infection. It may feel warm and tender.
When to see a doctor
While monitoring a swollen lymph node for a few weeks is reasonable, certain signs warrant a prompt medical evaluation.
Seek immediate medical attention if you experience any of the following alongside swollen lymph nodes:
- Difficulty breathing or swallowing.
- A rapidly growing or very painful lymph node.
- Redness or pus draining from the area over the lymph node.
Make an appointment with your healthcare provider if you have a swollen lymph node that:
- Appears for no obvious reason, such as a known cold or infection.
- Persists for more than two to four weeks.
- Feels hard, rubbery, or fixed in place.
- Is accompanied by other constitutional symptoms, such as persistent fever, drenching night sweats, or unexplained weight loss.
Conclusion
In most instances, a swollen lymph node is simply a sign of your immune system doing its job. By paying close attention to its characteristics—including how it feels, its size, and how long it lasts—you can better understand its cause. While the vast majority of cases are benign, it's crucial to know the warning signs that indicate a need for professional medical evaluation. When in doubt, consulting a healthcare professional can provide peace of mind and ensure any potentially serious conditions are addressed promptly. To explore more about lymph node function and disorders, consult this resource from the Cleveland Clinic: Lymph Node Locations & Function.
