Swollen lymph nodes, especially in the neck, are a relatively common occurrence. They usually are a sign your body is fighting off a germy invader, but sometimes they indicate a far more serious problem.
Bottom Line Personal turned to Aaron Clark, DO, chair of Family & Community Medicine and clinical professor of Family Medicine at The Ohio State University, to better understand the lymphatic system and what causes swollen lymph nodes.
What Are Lymph Nodes?
Lymph nodes, small, bean-shaped structures, are part of your body’s lymphatic system, which is part of your immune system. Think of the lymphatic system as a network of channels that run parallel to and work with the circulatory system and lymph nodes as checkpoints along the way, says Dr. Clark. There are hundreds of lymph nodes throughout the body, primarily in the neck, armpits, groin and abdomen.
“Their main job is to filter lymph, the fluid excreted by various tissues,” says Dr. Clark. But when your immune system senses a virus or other invader, the lymph nodes create antibodies to fight it off. “They get swollen while they’re doing that work,” he explains, pointing out that even though they might feel tender and even painful, that’s a sign they’re functioning as they should.
What Causes Swollen Lymph Nodes?
“Many physiologic processes take place within the lymphatic system,” Dr. Clark explains. That’s why infections are just one of the reasons—albeit the most common one—for swollen lymph nodes. Here’s what you need to know about the primary culprits for swollen lymph nodes…
Infections
“Swollen lymph nodes in the neck almost always are in response to some sort of viral upper-respiratory infection,” says Dr. Clark. While some call it having “swollen glands,” the swelling occurs in the lymph nodes. “There are some viruses that are a little bit more prone to creating swelling in the lymph nodes,” he adds. “Cytomegalovirus (CMV), which can mimic flu, and Epstein-Barr virus (or mono) are two classic ones that usually cause a severe sore throat along with markedly swollen lymph nodes in the region around the neck.” HIV and tuberculosis are other possible causes. “The herpes simplex virus (HSV) classically creates quite a large number of inflamed lymph nodes in the groin,” Dr. Clark says.
Virtually any viral or bacterial infection can activate lymph nodes. “If you had a cut on your face or scalp that got infected, the regional lymph nodes would likely become tender and swollen as part of the response to that.” The bacterial infection known commonly as cat scratch disease can cause swollen lymph nodes in the upper body, especially in the armpit—or close to wherever the cat scratched you, he adds. The often cat-related parasitic infection toxoplasmosis also can lead to swollen lymph nodes.
One hallmark of this type of response to an infection is that, while the lymph nodes involved can be swollen, tender and painful, they’re also soft and freely mobile. “You can kind of wiggle them around,” Dr. Clark describes. “Once you treat the infection, then the lymph node no longer needs to be working as hard, so it ‘stands down’—everything disperses and goes back to what it was.”
Though discomfort means a lymph node is doing its job, you can apply heat or ice to the area—whichever feels better—and see if that calms down some of that sensation, he advises. “Massaging or rubbing is not a great idea and will probably cause more irritation than anything else. If you can tolerate ibuprofen or acetaminophen (Tylenol), those can help reduce some of the pain, too.”
Autoimmune diseases
With conditions like lupus and rheumatoid arthritis, you could experience enlargement of lymph nodes as your immune system mistakenly goes into overdrive to fight off the perceived invader, Dr. Clark explains. The swelling is unlikely to resolve until you get appropriate treatment, and a newly swollen lymph node can be a sign of a flare.
Cancers
The lymphatic system itself can develop cancer, notably Hodgkin lymphoma and non-Hodgkin lymphoma, with a swollen lymph node often being the earliest symptom (other symptoms include fevers, chills, night sweats and unexplained weight loss). Swollen lymph nodes can be a sign of head and neck cancers. Cancers of the blood, such as leukemias, often start in the bone marrow and can lead to swollen lymph nodes.
Other types of cancer can metastasize or spread through the lymphatic network. “The lymph system transports fluids throughout the whole body, so if cancer cells get into the lymphatic system, it’s like an expressway to get anywhere else in the body,” explains Dr. Clark. Example: Breast cancer can spread through the lymphatic system and get into the lymph nodes. Those lymph nodes will show evidence of that same cancer that originally was in the breast. To prevent such a spread or, if the surgeon suspects there’s already lymph node involvement, lymph nodes may be removed during breast cancer surgery.
When swollen lymph nodes are due to a cancer, they tend to be fixed in place with firm edges—you can’t really move them around, says Dr. Clark. And they don’t go away, as will swollen lymph nodes caused by an infection after appropriate treatment.
Lymphedema
Because lymph nodes help regulate fluid balance, when some are removed, you can experience swelling called lymphedema. Women whose lymph nodes around the armpit are removed during breast cancer surgery may develop swelling in the adjacent arm. Men who have groin lymph nodes removed as part of prostate cancer surgery…and anyone having lymph nodes removed as part of colon cancer surgery…can experience swelling in areas such as the legs, groin or abdomen because of a buildup of lymphatic fluid—it can’t follow the normal pathways due to the surgical changes.
Medications
A handful of drugs can cause swollen lymph nodes as a side effect. The gout medicine allopurinol and the anti-seizure drug phenytoin are two examples, but there are dozens of others, including certain statins, blood pressure medications and antibiotics. Contact your doctor immediately if this happens—especially if you also have a fever and rash—to check for drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, a rare yet potentially serious condition.
Bottom line
“Patients come in with concerns because they found a new lump or bump or swelling somewhere on their body that wasn’t there before, and they want to know what that is,” says Dr. Clark. “When lymph nodes are swollen, it’s usually for a good reason, and you want them to do their job. But don’t ignore any swollen bump—whether you think it’s a lymph node or not—anywhere on your body, particularly if it’s solitary and hard. Get an evaluation so that any serious problem can be addressed early.”
