Lymphadenopathy (Swollen Lymph Nodes)
Lymphadenopathy refers to enlargement of lymph nodes — the small bean-shaped structures that filter immune cells throughout the body. Most cases are reactive to infection and resolve on their own.
Table of Contents
Quick Facts
- ICD-10: R59
- Most common cause: Infection (reactive)
Common Causes
Infections
- Viral (cold, flu, mononucleosis, COVID-19)
- Bacterial (strep, dental, skin infections)
- Tuberculosis
- HIV
Immune
- Autoimmune diseases (lupus, rheumatoid arthritis)
- Reaction to vaccinations
Cancer
- Lymphoma
- Leukemia
- Metastatic cancer spread to nodes
Medications
- Phenytoin, allopurinol, some others
Concerning Features
- Lymph node > 1 cm in an adult, not from a clear infection
- Persistently enlarged (>3–4 weeks)
- Hard, fixed, painless
- Above the collarbone (supraclavicular)
- Associated with fever, weight loss, night sweats
- Generalized enlargement in multiple regions
When to See a Doctor
See a doctor for nodes that meet any of the concerning features above. Most lymphadenopathy is benign, but appropriate evaluation distinguishes reactive nodes from those needing further workup.
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.
References
- American Academy of Family Physicians. Lymphadenopathy Evaluation.