Should I worry when my lymph nodes are swollen?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: July 9, 2025Updated: July 9, 2025

Summary

Lymph nodes enlarge because immune cells inside them are multiplying to fight a trigger—most often a viral or bacterial infection close to the node. Swelling that lasts under three weeks, is tender, and shrinks as you recover is usually benign. Painless nodes larger than 1.5 cm, especially above the collarbone, or any node that keeps growing beyond one month needs prompt medical evaluation to rule out cancers, autoimmune disease, or rare infections.

Why do lymph nodes get bigger in the first place?

Nodes act like tiny security checkpoints. When germs, damaged cells, or cancer cells pass through, immune cells inside the node multiply and release fluid, making the node swell.

  • Infections trigger rapid immune cell growthAbout 80-90 % of short-term swollen nodes are caused by common viruses (colds, flu, COVID-19) or bacteria (strep throat, skin boils) in the nearby area.
  • Inflammatory conditions also enlarge nodesDiseases such as rheumatoid arthritis or lupus cause a persistent immune attack that keeps nodes mildly enlarged for months.
  • Cancer cells can seed a nodeAbout 4 % of adult nodes biopsied in primary care turn out to be lymphoma, leukemia, or metastatic cancer, most often when the node is painless and firm.
  • Medications play a lesser-known roleDrugs like phenytoin and certain antibiotics can cause a hypersensitivity reaction called DRESS, leading to generalized lymphadenopathy.
  • Expert insight“Think of swelling as a visible sign of how busy the immune system is inside that node,” explains Sina Hartung, MMSC-BMI.
  • Swelling pattern offers diagnostic cluesPainful, rapid enlargement usually signals an infection or injury, while slow, painless growth may indicate lymphoma or metastatic cancer. (NIH)
  • Node location points to the problem areaNeck nodes enlarge with colds or sore throats, armpit nodes after arm infections, and generalized swelling can follow viral illnesses or certain medications. (Kaiser)

References

Which swollen lymph nodes should raise an immediate red flag?

Location, size, texture, and associated symptoms matter more than the fact that a node is swollen.

  • Hard supraclavicular nodes signal higher riskAny node above the collarbone larger than 1 cm has a 25 % chance of being malignant and warrants same-week imaging.
  • Nodes over 2 cm persisting past four weeksA diameter above 2 cm that does not regress after antibiotics needs ultrasound or CT regardless of pain level.
  • B symptoms point to lymphomaNight sweats drenching clothes, unexplained fever over 38 °C, and weight loss over 10 % in six months plus swollen nodes suggest possible lymphoma.
  • Rapidly growing single node in childrenA node that doubles in size within 48 hours may indicate an abscess needing surgical drainage.
  • Doctor’s note“Texture tells me a lot—rock-hard, fixed nodes behave differently from soft, mobile ones,” notes the team at Eureka Health.
  • Painless nodes ≥1 cm that stay enlarged for more than two weeks are worrisomeCancer becomes a stronger possibility when a lymph node is at least 1 cm, non-tender, and fails to shrink after roughly 14 days—especially in adults with risk factors like smoking or HPV. (Cleveland Clinic)
  • Swelling in two or more nodal regions suggests a systemic diseaseGeneralized lymphadenopathy can signal viral or bacterial infections, medication reactions, cancers such as lymphoma or leukemia, or HIV/AIDS and warrants lab work rather than watchful waiting. (Kaiser)

References

Can I tell at home if it is just an infection?

You cannot make a definite diagnosis without a clinician, but certain patterns lean toward a benign cause.

  • Tenderness usually means infectionMore than 90 % of painful cervical nodes in adults are reactive to viral or bacterial illness.
  • Multiple small nodes on both sidesSymmetrical enlargement under 1.5 cm in the neck or groin after a cold almost always resolves within three weeks.
  • Skin redness over node hints at local sourceCellulitis or infected insect bites near the node cause warmth and redness in up to 30 % of cases.
  • Age mattersChildren under 12 routinely develop pea-sized neck nodes after routine vaccinations—this is expected and self-limited.
  • Professional perspective“Track the size daily with a ruler; shrinking nodes are reassuring,” advises Sina Hartung, MMSC-BMI.
  • Swelling that lasts more than two weeks needs medical reviewHealthdirect recommends seeing a doctor if a lymph node stays enlarged for over 2 weeks, even when other symptoms are mild. (Healthdirect)
  • Hard or immobile nodes are warning signsMayo Clinic notes that lymph nodes which feel hard, rubbery, or do not move under the skin should be evaluated promptly because they can indicate a more serious cause than infection. (Mayo)

References

What self-care helps while waiting to see a clinician?

Support the immune response and ease discomfort, but avoid aggressive manipulation or unproven remedies.

  • Warm compresses reduce sorenessA clean, moist heat pack for 10-15 minutes three times daily improves blood flow and eases pain.
  • Stay hydrated and restAim for 30 mL/kg of water daily; dehydration slows lymphatic drainage and may prolong swelling.
  • Over-the-counter pain relief, if safe for youAcetaminophen or an NSAID taken at the labeled dose can cut node tenderness; check with a pharmacist if you have liver, kidney, or stomach problems.
  • Avoid constant poking or massageRepeated squeezing may inflame tissues and delay recovery.
  • Expert guidanceThe team at Eureka Health reminds, “If swelling worsens despite these measures, book an appointment within 24 hours.”
  • Seek help if swelling lasts beyond two weeksParkview Health advises seeing a clinician when a node remains enlarged for more than 14 days, gets increasingly red or tender, or if several areas of glands are swollen. (Parkview)
  • Never squeeze, drain, or puncture a nodeKaiser Permanente warns that trying to manipulate a swollen lymph node can worsen infection and delay healing, so leave any drainage to medical professionals. (KP)

References

Which labs, imaging, or medications might be ordered?

Your clinician’s choices depend on the node’s characteristics and your history.

  • Complete blood count checks infection patternsElevated neutrophils suggest bacterial infection; atypical lymphocytes raise suspicion for mononucleosis or leukemia.
  • Ultrasound distinguishes cystic from solid massesA hypoechoic, well-defined node with a fatty hilum is usually benign, whereas loss of the hilum and increased vascularity raises concern.
  • Targeted serology testsEBV IgM, HIV antigen/antibody, and Bartonella henselae titers are common when exposure history fits.
  • Empiric antibiotics for bacterial lymphadenitisIf cellulitis or strep throat is suspected, a 7-10-day course of a beta-lactam is frequently prescribed after culture swabs if possible.
  • Quote on diagnostics“We escalate from blood work to biopsy only when non-invasive tests still leave doubt,” explains Sina Hartung, MMSC-BMI.
  • Chest X-ray or CT assesses deep lymphadenopathyMayo Clinic advises ordering radiographic imaging when malignancy or intrathoracic disease is suspected, allowing visualization of mediastinal nodes or potential primary tumors. (Mayo Clinic)
  • Nodes unresolved after 3–4 weeks often lead to biopsyThe Merck Manual states that persistent enlargement beyond 3–4 weeks typically prompts more specific testing and may necessitate excisional biopsy to rule out cancer. (Merck)

References

How Eureka’s AI doctor guides swollen-node concerns

Our AI chat collects your symptoms, duration, and risk factors, then offers next-step advice that aligns with evidence-based algorithms.

  • Instant triage recommendationsThe AI flags red-flag patterns like supraclavicular nodes over 1 cm and advises urgent care.
  • Personalized testing suggestionsIf mononucleosis is likely, the system proposes an EBV panel that our medical team can approve and order.
  • Medication review and safety checksThe AI highlights drug interactions before a clinician prescribes an antibiotic.
  • Symptom tracking dashboardDaily size and pain logs are charted, helping you and your clinician spot improvement or deterioration.
  • Eureka clinician reassuranceThe team at Eureka Health notes, “Patients who upload photos of nodes receive clearer guidance and avoid unnecessary ER visits.”

What users say about Eureka for lymph node worries

People appreciate having a private, structured space to ask delicate questions.

  • High satisfaction among infection casesUsers with viral nodes rate the lymph-node pathway 4.7 / 5 for clarity.
  • Reduced unnecessary clinic visitsIn an internal audit, 38 % of users avoided same-day urgent care after receiving self-care instructions and red-flag education.
  • Safe prescription workflowWhen antibiotics are indicated, requests are reviewed by licensed physicians within two hours.
  • Data privacy maintainedAll photos and chats are encrypted end-to-end and deleted after 30 days unless you opt to store them.
  • Remark from the developers“Women using Eureka for menopause rate the app 4.8 out of 5 stars; we strive for the same trust on immune issues,” says Sina Hartung, MMSC-BMI.

Become your own doctor

Eureka is an expert medical AI built for WebMD warriors and ChatGPT health hackers.

Learn More

Frequently Asked Questions

How big is too big for a lymph node?

In adults, any node larger than 1.5 cm in the neck or 1 cm above the collarbone should be examined by a clinician.

Can allergies cause swollen lymph nodes?

Seasonal allergies rarely enlarge nodes; if they do, swelling is mild and resolves once allergen exposure drops.

Do I need antibiotics for every swollen node?

No—most nodes are viral. Antibiotics help only when a bacterial infection is confirmed or strongly suspected.

Is a painless armpit node after COVID-19 vaccination normal?

Yes, up to 16 % of people develop temporary axillary swelling on the side of the shot; it fades within six weeks.

How long should a child’s neck node stay enlarged after strep throat?

It usually shrinks within two weeks of starting antibiotics; full normalization can take four weeks.

Can stress alone enlarge lymph nodes?

Stress does not directly swell nodes but may make you more aware of normal, small nodes that were always present.

Should I get a biopsy right away if cancer runs in my family?

Family history is important, but biopsy is reserved for nodes that meet size, duration, or ultrasound criteria suggesting malignancy.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

General References

Back to Resources