Why am I so tired and my glands are swollen?: Understanding the Causes

September 30, 2025 •

4 min read

According to the Mayo Clinic, swollen lymph nodes are a common sign that the body is fighting an infection, with viral infections being the most frequent cause. If you've been asking, Why am I so tired and my glands are swollen?, it's likely your immune system is hard at work, but the combination of these two symptoms can signal a variety of conditions, both common and more serious.

Quick Summary

The combination of persistent fatigue and swollen glands, or lymph nodes, indicates your body's immune system is actively responding to an illness. This can range from a routine viral or bacterial infection like mononucleosis to more complex conditions involving the immune system or, in rare cases, cancer.

Key Points

Common Causes: Most cases of fatigue and swollen glands are due to common viral infections like mononucleosis, colds, or the flu, which typically resolve on their own with rest.
Persistent or Worsening Symptoms: A visit to the doctor is recommended if swollen glands last longer than two weeks, continue to grow, or are accompanied by fever, night sweats, or unexplained weight loss.
Identifying Red Flags: Glands that are hard, fixed, and painless may signal a more serious underlying condition, such as lymphoma, and should be evaluated by a healthcare provider.
Diagnostic Process: Doctors use physical exams, blood tests (like the Monospot test), imaging, and sometimes a biopsy to determine the root cause of the symptoms.
Treatment Approach: Treatment is dependent on the diagnosis and can range from rest and fluids for a viral illness to antibiotics for bacterial infections, or more specialized care for autoimmune diseases or cancer.
Lymph Node Function: Swollen glands, or lymph nodes, indicate your immune system is fighting an infection by filtering pathogens and producing infection-fighting cells.

The Lymphatic System and Swollen Glands

To understand why your glands swell, you must first know their role. The 'glands' people refer to are actually lymph nodes, small, bean-shaped organs that are a crucial part of your body's lymphatic system. They act as filters, trapping viruses, bacteria, and other pathogens before they can spread further through the body. When your body detects an infection, your lymph nodes produce more infection-fighting white blood cells, causing them to swell and become tender.

These nodes are located throughout the body, including the neck, groin, and armpits, and their swelling is a clear sign that your immune system is active. While this is usually a normal response to a benign infection, prolonged swelling combined with fatigue warrants further investigation.

Common Infectious Causes

Many of the most frequent reasons for simultaneous fatigue and swollen glands are infectious in nature. Fortunately, most of these are temporary and resolve with supportive care.

Viral Infections

Mononucleosis (Mono): Often called 'the kissing disease,' mono is a classic culprit for these symptoms. Caused by the Epstein-Barr virus (EBV), it leads to extreme fatigue, fever, sore throat, and significantly swollen lymph nodes, especially in the neck and armpits. The fatigue can be prolonged, lasting for weeks or months after other symptoms subside.
Common Cold and Flu: These everyday viruses cause generalized fatigue and can lead to swollen lymph nodes as the body fights the infection. Symptoms typically resolve within a week or two.
Cytomegalovirus (CMV): A virus from the herpes family, CMV can cause mono-like symptoms, including fatigue and swollen glands.
HIV: In its early stages, HIV can cause flu-like symptoms, including fatigue and swollen lymph nodes throughout the body.

Bacterial Infections

Strep Throat: This bacterial infection of the throat causes a sore throat and can be accompanied by fever and swollen glands in the neck. It requires antibiotic treatment.
Dental Abscess or Infected Tooth: An infection in the mouth can cause nearby lymph nodes under the jaw to swell.
Skin Infections: Bacterial skin infections like cellulitis can cause regional lymph nodes to swell.

Non-Infectious and Systemic Causes

Beyond common infections, several other medical conditions can cause chronic fatigue and swollen lymph nodes. These often require a more specific diagnosis and treatment.

Autoimmune Diseases

In autoimmune conditions, the body's immune system mistakenly attacks its own healthy cells. This constant state of inflammation can lead to both fatigue and lymph node swelling.

Lupus: Can affect any body system and is associated with fatigue, fever, and swollen glands.
Rheumatoid Arthritis: A chronic inflammatory disease affecting the joints, it can also cause systemic symptoms like fatigue and swollen glands.
Sarcoidosis: Causes inflammation of organ tissues and can begin with symptoms like extreme tiredness and swollen lymph nodes.

Cancer

While rare, certain cancers can manifest with prolonged fatigue and swollen glands.

Lymphoma: This is a cancer of the lymphatic system itself, where cancerous lymphocytes grow uncontrollably and cause lymph nodes to swell. It often presents with additional symptoms like unexplained weight loss, night sweats, and persistent fever.
Leukemia: A cancer of the blood, it can cause lymph nodes to swell and is associated with fatigue.

Comparison of Common Causes


Condition	Onset	Duration	Gland Characteristics	Severity	Additional Symptoms
Common Cold	Rapid	1-2 weeks	Soft, tender, movable	Mild	Runny nose, cough, sore throat
Mononucleosis	Gradual	Weeks to months	Significantly swollen, tender	Moderate to severe	Extreme fatigue, fever, sore throat
Bacterial Infection (e.g., Strep)	Rapid	Days to weeks	Tender, often localized	Moderate	Fever, specific infection symptoms
Autoimmune Disease	Gradual	Chronic	Can be persistent or recurring	Varies	Joint pain, rash, organ-specific symptoms
Lymphoma	Gradual	Persistent	Firm, non-tender, fixed	Severe	Weight loss, night sweats, persistent fever

When to See a Doctor

It is important to monitor your symptoms and seek medical advice when necessary. See a healthcare professional if you experience the following:

Swollen lymph nodes that appear for no obvious reason or increase in size.
Swelling persists for more than two weeks.
The nodes feel hard or rubbery and don't move when pushed.
Your symptoms are accompanied by a fever that won't go away, night sweats, or unexplained weight loss.
You have difficulty breathing or swallowing.

Diagnosis and Treatment

Diagnosis

Your doctor will perform a physical examination to check your lymph nodes and inquire about other symptoms. The diagnostic process may include:

Blood Tests: A complete blood count (CBC) or a monospot test can help confirm or rule out infections like mono. Blood tests can also help detect signs of other conditions, including autoimmune disorders or leukemia.
Imaging: For persistent or concerning swelling, imaging tests like a CT scan or ultrasound may be ordered to get a better view of the lymph nodes and surrounding tissues.
Biopsy: If cancer is suspected, a biopsy of the lymph node is the definitive diagnostic test.

Treatment

Treatment depends entirely on the underlying cause:

Viral Infections: For viruses like mono, treatment focuses on supportive care, including rest, fluids, and over-the-counter pain relievers.
Bacterial Infections: Antibiotics are prescribed to treat bacterial infections like strep throat.
Autoimmune Conditions: These require specific management strategies to control the immune response and manage inflammation.
Cancer: Treatment for lymphoma or other cancers can include surgery, radiation therapy, or chemotherapy.

Conclusion

The dual symptoms of fatigue and swollen glands are a clear indication that your body is actively engaged in an immune response. While the most likely cause is a common infection that will resolve on its own, it is crucial to pay attention to the duration and nature of your symptoms. Persistent, unexplained, or severe symptoms warrant a visit to a healthcare provider for a proper diagnosis. By understanding the potential causes, you can take appropriate action and ensure you receive the right care for a full recovery.

Authoritative Link

For more information on the lymphatic system and swollen lymph nodes, see the Mayo Clinic's guide on Swollen lymph nodes.

Frequently Asked Questions

The most common cause of fatigue and swollen glands is a viral infection, such as mononucleosis (glandular fever) caused by the Epstein-Barr virus.

While most swollen glands from infections are soft and movable, glands that are hard, rubbery, and fixed in place may be a warning sign of a more serious condition like cancer (lymphoma) and require medical evaluation.

You should see a doctor if your swollen glands persist for more than two to four weeks, increase in size, or have no obvious cause.

While stress can cause or worsen fatigue, it is not a direct cause of swollen glands. However, chronic stress can weaken your immune system, making you more susceptible to infections that cause swelling.

Yes, while most mono symptoms resolve within a couple of weeks, the accompanying fatigue can linger for several weeks or even months after the initial infection has cleared.

Yes, autoimmune diseases like lupus, rheumatoid arthritis, and sarcoidosis cause chronic inflammation that can lead to persistent fatigue and swollen glands.

Antibiotics are only effective against bacterial infections. They will not help with viral infections like mono or the common cold. Your doctor will determine if an antibiotic is necessary based on the cause of your symptoms.