Swollen lymph nodes can be concerning. This article explores the relationship between COVID-19 and lymph node swelling, explains the body’s immune response, discusses other common causes, and outlines when to consult a healthcare professional.
COVID-19 and Lymph Node Swelling
COVID-19 can cause swollen lymph nodes, known as lymphadenopathy, as the body’s immune system responds to the viral infection. When the virus enters the body, immune cells in the lymph nodes become activated to fight off the pathogen, leading to their enlargement. Swollen lymph nodes due to COVID-19 are not among the most common symptoms but can occur even with mild infections.
The swelling typically appears in lymph nodes close to the infection site. For instance, if COVID-19 causes throat inflammation or respiratory symptoms like cough and congestion, lymph nodes in the neck may swell. Axillary (armpit) lymph nodes can also become swollen, particularly following COVID-19 vaccination, as a sign of an immune response to the vaccine. The prevalence of thoracic lymphadenopathy (swollen lymph nodes in the chest) in COVID-19 patients has been reported at around 16.7%. While the swelling can be painful, it often resolves within a few weeks as the body recovers. In some cases, vaccine-induced lymph node swelling may persist longer, sometimes for several months.
The Immune System’s Response
Lymph nodes are small, bean-shaped structures integral to the lymphatic system, a component of the immune system. These nodes are strategically located throughout the body, including the neck, armpits, and groin, and act as filters for lymph fluid. Lymph fluid, which contains white blood cells, travels through these nodes, carrying waste products and foreign substances like bacteria and viruses.
When the body encounters an infection, immune cells within the lymph nodes, including lymphocytes, multiply rapidly to fight pathogens. This increased activity and trapping of foreign matter cause the lymph nodes to enlarge. This swelling is a sign that the immune system is actively working to clear the infection. Lymph nodes serve as crucial meeting points where immune cells like lymphocytes and antigen-presenting cells interact to initiate a targeted immune response.
Other Common Causes of Swollen Lymph Nodes
While COVID-19 can lead to swollen lymph nodes, many other conditions can also cause this symptom. The most frequent cause is infection, often viral, like the common cold or flu. Upper respiratory infections commonly result in swollen lymph nodes in the neck.
Other viral infections like mononucleosis, measles, and HIV can also cause lymph node swelling. Bacterial infections, including strep throat, skin infections like cellulitis, and even an infected tooth, are common culprits. Less common causes include autoimmune diseases like lupus and rheumatoid arthritis, and rarely, cancers like lymphoma or leukemia. The location of the swollen lymph nodes can sometimes provide a clue to the underlying cause, as they tend to swell near the site of infection or disease.
When to Seek Medical Advice
Most instances of swollen lymph nodes are harmless and resolve on their own as the underlying infection clears. However, specific signs and symptoms warrant medical evaluation. It is advisable to consult a healthcare professional if the swollen lymph nodes have no clear reason, continue to get larger, or remain swollen for more than two to four weeks.
Other concerning symptoms include lymph nodes that feel hard, rubbery, or fixed in place, rather than soft and movable. Accompanying symptoms such as persistent fever, night sweats, unexplained weight loss, difficulty swallowing or breathing, or red and inflamed skin over the nodes should prompt a medical visit. For mild discomfort, applying a warm compress and taking over-the-counter pain relievers like ibuprofen or acetaminophen can help manage symptoms.