Dog With Swollen Glands: Causes, Diagnosis, and Treatment Options

Noticing a lump or swollen area on your dog can be alarming. When those swellings appear under the jaw, behind the knees, or near the shoulders, you may be dealing with lymphadenopathy — the medical term for enlarged lymph nodes. A dog with swollen glands is exhibiting a symptom, not a single disease; swollen lymph nodes can signal anything from a routine bacterial infection to lymphoma, one of the most common canine cancers. According to the Merck Veterinary Manual, lymphoma accounts for roughly 7–24% of all canine cancers, and swollen lymph nodes are often the first visible clue. Lymph nodes are small, bean-shaped structures distributed throughout your dog's body that filter lymph fluid and house immune cells. When they enlarge, it means the immune system is actively responding to something — but what it's responding to requires veterinary investigation.

This guide breaks down every plausible cause of swollen glands in dogs, the diagnostic process you can expect, realistic treatment costs in 2026, and the red-flag symptoms that demand an immediate vet visit. Always consult your veterinarian for an accurate diagnosis — this article is educational and does not replace professional veterinary care.

What Are Swollen Glands in Dogs?

When people say "swollen glands" in dogs, they are almost always referring to peripheral lymph nodes — the ones you can feel through the skin. Dogs have several pairs of easily palpable lymph nodes:

• Submandibular — under the jaw (most commonly noticed)
• Prescapular — in front of the shoulders
• Axillary — in the armpit area
• Inguinal — in the groin
• Popliteal — behind the knee (stifle joint)

Normal lymph nodes in dogs are typically small, firm, and difficult to feel — roughly the size of a pea to a small kidney bean depending on the dog's size. When they become enlarged, they may feel like soft or firm lumps ranging from grape-sized to golf-ball-sized or larger. The medical term for this enlargement is lymphadenopathy, and it falls into two categories:

• Lymphoid hyperplasia (reactive lymphadenopathy): The lymph nodes are responding normally to an immune trigger — infection, inflammation, or immune-mediated disease. The nodes are doing their job, just working overtime.
• Lymphadenitis: The lymph nodes themselves are infected or inflamed, often due to bacterial or fungal invasion.
• Neoplastic lymphadenopathy: Cancer cells — either primary lymphoma or metastatic cancer from another organ — are infiltrating the lymph node tissue.

Symptoms of Swollen Glands in Dogs: Early Warnings vs. Advanced Signs

Swollen lymph nodes rarely exist in isolation. The accompanying symptoms often point toward the underlying cause. Here is a severity-organized checklist to help you communicate effectively with your vet.

Risk Factors: Which Dogs Are Most Likely to Develop Swollen Glands?

How Veterinarians Diagnose the Cause of Swollen Glands

Arriving at a diagnosis is a process of elimination. Your vet will follow a structured diagnostic pathway, starting with the least invasive tests and escalating as needed. Here is what to expect at each stage.

Step 1: Physical Examination and History ($60–$120)
Your vet will palpate all peripheral lymph node groups, assess node size, texture, and mobility, check body temperature, listen to heart and lungs, and examine mucous membranes. Expect detailed questions about symptom onset, travel history, tick exposure, vaccination timing, and diet. This visit alone may narrow the possibilities significantly.

Step 2: Fine Needle Aspirate (FNA) and Cytology ($75–$200)
This is often the pivotal diagnostic test. A thin needle is inserted into the enlarged lymph node to extract cells, which are then examined under a microscope. FNA can distinguish between reactive hyperplasia (normal immune cells in high numbers), lymphadenitis (bacteria or inflammatory cells), and neoplasia (cancer cells). Results may be available same-day if your vet has an in-house pathologist, or in 2–5 days if samples are sent to an external laboratory like IDEXX or Antech Diagnostics. FNA has a diagnostic accuracy of approximately 80–90% for lymphoma, according to peer-reviewed veterinary oncology literature.

Step 3: Complete Blood Count (CBC) and Chemistry Panel ($120–$250)
Blood work reveals systemic clues: elevated white blood cell counts suggest infection or inflammation; anemia may indicate bone marrow involvement; elevated liver enzymes or calcium levels (hypercalcemia) can point toward lymphoma. A CBC with differential and a comprehensive chemistry panel together give your vet a broad metabolic picture.

Step 4: Advanced Imaging — X-rays and Ultrasound ($250–$600)
Thoracic radiographs (chest X-rays) check for mediastinal lymph node enlargement, which affects staging and prognosis. Abdominal ultrasound evaluates internal lymph nodes, spleen, and liver for involvement. Together, these imaging studies determine how widespread the condition is — critical information for staging lymphoma if that is the diagnosis.

Step 5: Biopsy and Histopathology ($300–$800)
If FNA results are inconclusive or if your vet needs to determine the specific lymphoma subtype (B-cell vs. T-cell), a surgical biopsy — either a core needle biopsy or complete excision of one lymph node — is sent for histopathological evaluation. This takes 5–10 business days and is performed under sedation or general anesthesia. B-cell lymphoma generally carries a more favorable prognosis than T-cell lymphoma, making this distinction clinically important.

Step 6: Specialized Testing ($200–$600+)
Depending on suspected cause, additional tests may include tick-borne disease panels (4Dx or PCR panels for Ehrlichia, Anaplasma, Borrelia), fungal titers (Histoplasma, Blastomyces, Coccidioides antigen/antibody tests), flow cytometry (to characterize lymphocyte populations), or PARR testing (PCR for Antigen Receptor Rearrangement, which helps confirm clonal lymphocyte populations indicative of lymphoma).

Common Causes of Swollen Glands in Dogs

Understanding the range of possible causes helps you have a more informed conversation with your veterinarian. The following conditions represent the most frequently diagnosed reasons for canine lymphadenopathy.

Infectious Causes

Bacterial infections — Dental abscesses, skin wounds, ear infections, and systemic bacterial diseases like leptospirosis can trigger reactive lymph node enlargement. The submandibular nodes (under the jaw) often swell in response to dental or oral infections. Antibiotics targeting the primary infection typically resolve the lymph node swelling within 1–3 weeks.

Tick-borne diseases — Ehrlichiosis, Anaplasmosis, Lyme disease, and Rocky Mountain Spotted Fever commonly cause generalized lymphadenopathy alongside fever, joint pain, and lethargy. Diagnosis is confirmed via SNAP 4Dx or PCR testing. Treatment with doxycycline (typically 10 mg/kg twice daily for 28 days) resolves most cases, though some dogs require supportive care for complications.

Fungal infections — Histoplasmosis, blastomycosis, and coccidioidomycosis (Valley Fever) are endemic in specific US regions and cause persistent lymph node enlargement, weight loss, and respiratory signs. Antifungal treatment with itraconazole or fluconazole often extends 3–6 months and can cost $200–$500 per month in medication alone.

Parasitic infections — Leishmaniasis (transmitted by sand flies, primarily in the southern US and Mediterranean regions) causes generalized lymphadenopathy, skin lesions, and kidney damage. Treatment is prolonged and relapse is common.

Immune-Mediated and Inflammatory Causes

Conditions like immune-mediated hemolytic anemia (IMHA), systemic lupus erythematosus (SLE), and drug reactions can cause reactive lymphadenopathy. Recent vaccinations (especially modified-live vaccines) can produce mild, temporary lymph node enlargement that resolves within 2–4 weeks without treatment.

Neoplastic Causes (Cancer)

Lymphoma is the most concerning cause of swollen glands in dogs. It is broadly categorized into five anatomical forms: multicentric (most common, ~80% of cases, affecting external lymph nodes), alimentary (gastrointestinal), mediastinal (chest), extranodal (skin, kidneys, CNS), and cutaneous. Within multicentric lymphoma, the subtypes B-cell and T-cell carry different prognoses.

Metastatic cancer — Cancers originating elsewhere (mast cell tumors, melanomas, carcinomas) can spread to regional lymph nodes. A dog with a mast cell tumor on its hind leg, for example, may develop an enlarged popliteal lymph node as the cancer metastasizes.

Treatment Options and Expected Outcomes

Treatment depends entirely on the underlying cause. Below is a comparison of the most common treatment pathways.

Canine lymphoma is treatable but rarely curable. The goal of chemotherapy in dogs differs from human oncology: veterinary protocols prioritize quality of life over aggressive cure attempts. Most dogs tolerate chemotherapy well — serious side effects (requiring hospitalization) occur in fewer than 5% of treatment sessions according to veterinary oncology data. Hair loss (alopecia) is minimal in most breeds, though continuously growing coats (Poodles, Bichon Frises, some Terriers) may experience noticeable thinning.

Prognosis by Stage and Severity

For lymphoma — the most prognostically significant cause of swollen glands — the World Health Organization (WHO) staging system is used:

Substage also matters: dogs classified as substage a (clinically well, eating normally, no systemic signs) have significantly better outcomes than those in substage b (showing systemic illness — lethargy, anorexia, vomiting). Hypercalcemia (elevated blood calcium) at diagnosis is a negative prognostic indicator most commonly associated with T-cell lymphoma.

For non-cancer causes, prognosis is generally favorable. Bacterial infections resolve fully with appropriate antibiotics. Tick-borne diseases respond well to doxycycline in the majority of cases. Fungal infections carry a more guarded prognosis and require long-term commitment to treatment.

Home Care, Monitoring, and Lifestyle Adjustments

Once your vet has established a diagnosis and treatment plan, your role at home is critical for monitoring progress and maintaining quality of life.

Daily Monitoring Protocol

• Lymph node measurement: Gently palpate affected lymph nodes 2–3 times per week. Use your fingers to estimate size (compare to common objects: pea, grape, walnut, golf ball). Record measurements in a logbook or phone notes to share with your vet at recheck appointments.
• Appetite and water intake: Track daily food consumption and water intake. Sudden changes can signal disease progression or medication side effects.
• Activity level: Note any changes in energy, willingness to exercise, or mobility. A simple 1–5 daily score in a journal helps track trends.
• Body weight: Weigh your dog weekly using a home scale (for small dogs, hold them on a bathroom scale and subtract your own weight). Unexplained weight loss is a key indicator to report.
• Temperature: If your vet recommends it, learn to take your dog's rectal temperature. Normal canine temperature is 101.0–102.5°F (38.3–39.2°C). Fever above 103.5°F (39.7°C) warrants a call to the clinic.

Lifestyle Adjustments During Treatment

• Nutrition: Dogs undergoing chemotherapy benefit from highly digestible, calorie-dense diets. Ask your vet about veterinary therapeutic diets such as Hill's Prescription Diet n/d or Royal Canin Recovery RS. If appetite is poor, warming food to body temperature (approximately 101°F / 38.3°C) and adding low-sodium chicken broth can improve palatability.
• Exercise: Moderate, low-impact exercise (short leash walks, gentle play) is encouraged unless your vet advises otherwise. Avoid strenuous activity during the 2–3 days following chemotherapy sessions when white blood cell counts may be at their lowest (nadir).
• Infection prevention: Dogs on chemotherapy are immunocompromised. Avoid dog parks, boarding facilities, and contact with sick animals during treatment. Keep vaccinations current before starting chemotherapy if possible — your vet will advise on timing.
• Medication management: If your dog is on prednisone (commonly prescribed alongside chemotherapy or as palliative monotherapy), expect increased thirst, urination, and appetite. Provide constant access to fresh water and more frequent bathroom breaks. Never stop prednisone abruptly — it must be tapered under veterinary guidance.

When to See the Vet: Red Flags That Require Immediate Attention

For non-emergency situations, schedule a veterinary appointment within 48–72 hours if you notice:

• Any new lump or swelling that persists beyond 5–7 days
• Lymph nodes that feel firm, fixed, or are growing gradually
• Mild appetite reduction lasting more than 2 days alongside swollen glands
• Unexplained weight loss of more than 5% of body weight
• Recurring fevers or persistent lethargy

Total Cost of Treating Swollen Glands in Dogs

Costs vary dramatically depending on the underlying diagnosis. Here are realistic budget ranges for 2026:

• Best-case scenario (reactive lymphadenopathy from minor infection): $150–$400 total — exam, FNA, antibiotics, one recheck visit.
• Mid-range scenario (tick-borne disease or fungal infection): $400–$3,500 — exam, FNA, blood work, specific pathogen testing, 1–6 months of medication, recheck visits.
• Worst-case scenario (lymphoma with full chemotherapy): $5,000–$12,000+ — full diagnostic workup (exam, FNA, biopsy, staging imaging, blood work), 19–25 week CHOP chemotherapy protocol, monitoring blood work between sessions, emergency visits for complications.
• Palliative-only lymphoma care: $500–$2,000 — prednisone and supportive medications, periodic recheck exams, quality of life assessments.

Pet insurance considerations: If you have an active pet insurance policy (such as Trupanion, Healthy Paws, or Nationwide) that was in place before symptom onset, lymphoma treatment is typically covered. Most policies reimburse 70–90% of eligible costs after the annual deductible. However, if swollen glands were noted in veterinary records before policy enrollment, the condition may be classified as pre-existing and excluded. Average monthly premiums for accident-and-illness coverage in 2026 range from $40–$90 depending on breed, age, and location.

Prevention Strategies

Not all causes of swollen glands are preventable, but you can reduce risk through these evidence-based measures:

• Year-round tick prevention: Use a veterinary-recommended isoxazoline-class product (Simparica, NexGard, Bravecto) or a topical alternative (Vectra 3D, Frontline Plus) to reduce tick-borne disease risk. Apply or administer on schedule without gaps.
• Regular wellness exams: Biannual veterinary checkups for dogs over 7 years old allow early detection of lymph node changes before they become obvious. Your vet palpates all peripheral nodes as part of a standard physical exam.
• Dental care: Daily tooth brushing and annual professional dental cleanings reduce oral bacteria that can cause submandibular lymph node reactivity. Dental disease is one of the most commonly overlooked causes of "swollen glands" under the jaw.
• Limit chemical exposure: Some epidemiological studies have suggested associations between herbicide/pesticide exposure and canine lymphoma risk. When possible, limit your dog's access to recently treated lawns and wash their paws after outdoor exposure.
• Know your breed's risk: If you own a predisposed breed (Golden Retriever, Boxer, Bull Mastiff, etc.), discuss baseline blood work and proactive monitoring with your veterinarian starting at age 5–6.
• Avoid geographic risk when possible: If you live in or travel to areas endemic for fungal infections (Ohio/Mississippi River valleys for Histoplasmosis, Southwest US for Valley Fever), discuss preventive strategies and early testing thresholds with your vet.

Frequently Asked Questions

What is the most common cause of swollen glands in dogs?

The most common cause is reactive lymphoid hyperplasia — the immune system responding to an infection, inflammation, or recent vaccination. However, in dogs over 6 years old with generalized (multiple-site) lymph node enlargement and no obvious infection, lymphoma becomes a leading concern that requires prompt veterinary investigation.

Can swollen glands in dogs go away on their own?

Yes, in some cases. If the swelling is related to a recent vaccination or a mild, self-limiting infection, lymph nodes may return to normal size within 2–4 weeks. However, any lymph node that remains enlarged beyond 7–10 days, continues to grow, or is accompanied by other symptoms should be evaluated by a veterinarian. Waiting too long can allow a treatable condition to progress to a more advanced stage.

How is lymphoma in dogs diagnosed?

Diagnosis typically begins with fine needle aspirate (FNA) cytology, which has 80–90% accuracy for detecting lymphoma. If FNA is inconclusive or if your vet needs to determine B-cell vs. T-cell subtype, a surgical biopsy with histopathology is performed. Staging then involves blood work, chest X-rays, and abdominal ultrasound to determine how far the disease has spread.

Can swollen glands in dogs be cured?

If the cause is infectious (bacterial, tick-borne, or some fungal infections), full cure is often achievable with appropriate medication. If the cause is lymphoma, the disease is considered treatable but not curable in the traditional sense — chemotherapy achieves remission in 80–90% of B-cell cases, but most dogs eventually relapse. Some dogs achieve long-term remission exceeding 2 years, which is considered a clinical success.

How much does lymphoma treatment cost for dogs?

A full CHOP chemotherapy protocol typically costs $4,000–$8,000 at a general practice and $6,000–$12,000+ at a veterinary specialty oncology center. Palliative treatment with prednisone alone costs $20–$80 per month. Newer treatments like Tanovea-CA1 (rabacfosadine) or single-agent doxorubicin protocols may fall in the $2,000–$5,000 range.

What is the life expectancy of a dog with swollen glands?

Life expectancy depends entirely on the cause. Dogs with infection-related lymphadenopathy have normal life expectancy once the underlying condition is treated. Dogs diagnosed with multicentric B-cell lymphoma who receive CHOP chemotherapy have a median survival of 12–18 months, with approximately 20–25% surviving beyond 2 years. Dogs with untreated lymphoma typically survive 4–6 weeks from the onset of clinical signs.

Which breeds are most prone to lymphoma and swollen glands?

According to AVMA resources and veterinary oncology literature, breeds with the highest documented lymphoma incidence include Golden Retrievers, Boxers, Bull Mastiffs, Basset Hounds, Saint Bernards, Scottish Terriers, Airedale Terriers, Rottweilers, and Bernese Mountain Dogs. However, lymphoma can occur in any breed or mixed-breed dog.

Should I be worried if only one lymph node is swollen?

A single enlarged lymph node often points to a localized issue — a dental infection, skin wound, or ear infection near that node's drainage area. While less immediately concerning than generalized swelling, any single node that remains enlarged for more than 7–10 days, is firm or fixed, or continues to grow warrants a veterinary exam. In some cases, a single enlarged node can be the first sign of lymphoma or metastatic cancer.

Can allergies cause swollen glands in dogs?

Environmental allergies (atopic dermatitis) can cause mild reactive lymphadenopathy, particularly if secondary skin infections develop from scratching and chewing. Food allergies are less commonly associated with noticeable lymph node enlargement. If your dog has known allergies and you notice persistent lymph node swelling, your vet should rule out other causes rather than attributing it to allergies alone.