Why are my lymph nodes swollen in my neck and groin?

October 1, 2025 •

2 min read

The lymphatic system, a vital part of our immune defense, contains small, bean-shaped glands called lymph nodes that filter lymph fluid to remove waste and infectious organisms. When you notice swollen lymph nodes in my neck and groin, it's a common sign that your immune system is mounting an active response against an infection or illness.

Quick Summary

Swollen lymph nodes in the neck and groin typically signify an immune response to a local infection, but can also result from autoimmune conditions or, rarely, cancer. The location, duration, and associated symptoms are key indicators for assessing the cause and determining if a doctor visit is necessary.

Key Points

Immune Response: Swollen lymph nodes are most often a normal sign that your body's immune system is fighting an infection, such as a cold or strep throat.
Location is a Clue: Swelling location often points to the problem area; neck nodes react to head/throat issues, while groin nodes respond to infections in the legs or genitals.
Red Flags for Concern: Seek medical attention for swollen nodes that are hard, immobile, persist for more than 4 weeks, or are accompanied by unexplained weight loss or fever.
Beyond Infection: Besides common infections, causes can include autoimmune disorders like lupus, certain medications, or, in rare cases, cancers like lymphoma.
Diagnosis is Key: A medical history, physical exam, and potentially blood tests, imaging, or a biopsy are used to determine the exact cause.

Understanding the Lymphatic System

Your lymphatic system is a complex network of vessels, tissues, and organs crucial to your immune response. Lymph nodes, concentrated in areas like the neck, armpits, and groin, filter lymph fluid to trap foreign substances and pathogens. Swelling of these nodes, known as lymphadenopathy, indicates the immune system is active.

Common Infectious Causes

Infections are the most frequent cause of swollen lymph nodes, resulting from the accumulation of immune cells fighting pathogens. The location of the swollen node often suggests the site of the infection.

Common infections leading to swollen neck lymph nodes include:

Upper respiratory infections (cold, flu, strep throat)
Dental infections
Ear infections
Mononucleosis

Common infections leading to swollen groin lymph nodes include:

Sexually transmitted infections (STIs)
Skin or wound infections on the leg or foot
Fungal infections like jock itch or athlete's foot

Less Common, More Serious Causes

Beyond common infections, persistent or widespread lymphadenopathy can be linked to other conditions.

Autoimmune conditions: These occur when the immune system attacks healthy tissues. Examples include Lupus, Rheumatoid Arthritis, and Sjögren's Syndrome, all of which can cause lymph node swelling.

Cancer: Lymphoma and Leukemia are cancers of the blood or lymphatic system. Cancer from other body parts can also spread to lymph nodes, causing them to enlarge (metastatic cancer).

A Comparison of Lymph Node Characteristics

Distinguishing between benign and potentially serious causes of swollen lymph nodes involves evaluating several factors.


Feature	Typically Benign (Infection)	Potentially Concerning (Malignancy)
Onset	Sudden, often with illness.	Gradual, no clear cause.
Feel/Consistency	Soft, movable, often tender.	Hard, rubbery, fixed.
Duration	Resolves in 2-4 weeks.	Persists over 4 weeks or grows.
Associated Symptoms	Fever, sore throat, infection signs.	Weight loss, night sweats, persistent fever.
Location	Localized to infection area.	Generalized swelling in multiple areas.

When to Seek Medical Attention

Consult a healthcare provider if swollen lymph nodes exhibit concerning characteristics:

No obvious cause
Persist over four weeks or grow
Hard, rubbery, or immovable
Accompanied by persistent fever, night sweats, or unexplained weight loss
Located in the lower neck or above the collarbone
Cause difficulty swallowing or breathing

Diagnosis and Treatment

A doctor will conduct a physical exam and review medical history. Further tests may be needed for diagnosis.

Diagnostic Tools: Blood tests, imaging (ultrasound, CT scan), or a lymph node biopsy may be used.
Treatment Approaches: Treatment targets the underlying cause. Antibiotics for bacterial infections, rest for viral infections, specific medications for autoimmune disorders, and cancer treatments like chemotherapy, radiation, or surgery for malignancies.

Conclusion

Swollen lymph nodes in the neck and groin are often a temporary sign of the immune system fighting infection. However, persistent swelling or concerning symptoms warrant medical evaluation to determine the cause and ensure appropriate treatment. For additional reliable information, refer to the Mayo Clinic.

Frequently Asked Questions

The primary function of lymph nodes is to filter waste products, toxins, and infectious organisms from the body's lymphatic fluid, acting as a crucial part of the immune system.

Infections causing swollen lymph nodes in the neck often include viral illnesses like the common cold or mono, bacterial infections such as strep throat, and dental abscesses.

Swollen groin (inguinal) lymph nodes typically indicate an infection or injury in the legs, feet, or genitals. Sexually transmitted infections (STIs) and fungal infections like jock itch are common causes.

Swollen lymph nodes caused by a minor infection should typically decrease in size and resolve within two to four weeks. If swelling persists beyond this period, it is wise to see a doctor.

Cancerous lymph nodes often feel hard, rubbery, and are fixed in place, meaning they do not move easily when pushed. In contrast, nodes swollen from infection are usually soft, tender, and movable.

Yes, autoimmune disorders such as lupus and rheumatoid arthritis can cause swollen lymph nodes. This is because the immune system mistakenly attacks the body's own healthy tissues, causing inflammation and triggering lymph node enlargement.

You should see a doctor if your swollen lymph nodes have no apparent cause, persist for over four weeks, feel hard or fixed, or are accompanied by fever, night sweats, or unexplained weight loss.