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Enlarged Lymph Nodes in Dogs

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.

Unsure about what’s wrong with your pet? Feel free to use our Symptom Checker for more clarity

An enlargement of the lymph nodes in dogs refers to a Swelling of these small, bean-shaped organs that are part of the immune systemThe immune system is the body’s defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. This enlargement can indicate a variety of health problems, from infections to more serious diseases like cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas..

Can Occur with the Following Diseases:

Grundlagen und mögliche Ursachen

Lymph nodes are important components of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and act as filters for harmful substances such as bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. and viruses. They contain white blood cells that fight infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. When a dog is sick or has an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., the lymph nodes may swell as they produce more white blood cells to fight the disease.

The causes of swollen lymph nodes can be very diverse. Often, bacterial or viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. infections are the triggers. For example, infections of the Skin changes, ears, or teeth can lead to lymph node Swelling. Likewise, systemic infections such as distemper or Lyme disease may be involved.

Another reason for enlarged lymph nodes can be an allergic reaction. Allergies lead to an immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens., which can also be associated with a Swelling of the lymph nodes. Autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus., in which the body attacks its own cells, are also possible causes.

Serious diseases such as cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas., especially lymphomas, can also cause lymph node Swelling. In such cases, the lymph nodes enlarge because the cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. cells settle and multiply in them.

Typische Begleitsymptome

Fever: An increase in body temperature may indicate an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or Inflammatory conditions.
Lethargy and general weakness: Dogs with enlarged lymph nodes may be lethargic and less active than usual.
Loss of appetite: A dog that eats less or refuses food altogether may be suffering from an underlying condition.
Pain: Swollen lymph nodes can be painful, especially if caused by an inflammatory condition.
Cough or RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress: These symptoms may occur if the lymph nodes near the airways are enlarged.
Skin changes: Inflammatory conditions or infections of the skin can also lead to swollen lymph nodes.

Wann zum Tierarzt?

It is important to see a veterinarian if your dog’s lymph nodes are swollen, especially if the swelling lasts longer than a few days or is accompanied by other symptoms such as fever, weight loss, or RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress.

If the dog shows signs of Pain, is not eating or drinking, or if its behavior changes drastically, this should be considered an emergency. In such cases, it is advisable to seek veterinary help immediately to rule out or treat serious health problems.

Symptomerkennung für den Tierhalter und tierärztliches diagnostisches Vorgehen

The detection of swollen lymph nodes by the pet owner can be difficult because they are often deep in the tissue. However, nodules on the neck, under the armpits, or in the groin may be easier to feel. If you are unsure whether your dog’s lymph nodes are swollen, a gentle PalpationPalpation is an examination method in which the condition of body tissues is assessed by feeling them with the hands. It is used to identify swelling, pain, or other abnormalities. can help, but this should be done carefully to avoid causing Pain.

A veterinarian will begin the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. with a thorough clinical examination. This includes feeling the lymph nodes and checking for other symptoms. Blood tests may be necessary to identify infections or other diseases.

In some cases, the veterinarian may perform a fine-needle aspirationFine-needle aspiration is a minimally invasive diagnostic technique that uses a thin needle to extract cells or fluid from a tumor, lesion, or organ. This sample is then examined microscopically to make a diagnosis. or a Biopsie of the lymph nodes to collect cells and examine them under a microscope. These tests help determine the exact cause of the Swelling, especially if cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. is suspected.

Imaging techniques such as X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. can also be used to check the internal organs and other lymph nodes.

Was kann der Tierhalter tun und professionelle Therapieoptionen

The pet owner should make sure to give the dog rest and protect it from strenuous activities, especially if the dog shows signs of Lethargy or weakness. A suitable and balanced diet is also important to support the dog’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body..

It is advisable to keep the dog in a quiet, stress-free place and provide it with access to fresh water. Avoid moving the dog unnecessarily if it is obviously in Pain.

Avoid administering medication without consulting a veterinarian. Some human medications can be toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. to dogs. If the veterinarian prescribes medication, it should be administered exactly as directed.

It can be helpful to record the dog’s symptoms in a diary, including the frequency and duration of the Swelling as well as any accompanying symptoms. This information can help the veterinarian find the best treatment.

Ausblick auf aktuelle Forschung

The enlargement of the lymph nodes in dogs is a common symptom that can indicate a variety of underlying health conditions. Current research focuses on the development of non-invasive diagnostic tools to determine the cause of lymph node Swelling. Traditionally, the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through a combination of clinical examination, blood tests, and biopsies. New approaches explore the use of imaging techniques such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. and MRI to analyze the structure and composition of lymph nodes without surgical intervention.

Another area of research involves the study of genetic markers associated with lymph node Swelling and related diseases. By identifying specific genetic predispositions, veterinarians can better predict which dogs are at higher risk for certain diseases that lead to swollen lymph nodes. This research could enable personalized treatment approaches tailored to the individual genetic background of the dog.

In addition, the role of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. in the development of lymph node Swelling is being intensively researched. Scientists are investigating how immune responses to infections or Inflammatory conditions affect the lymph nodes and which immunomodulatoryImmunomodulatory describes the ability of a substance to modify the reaction of the immune system. Immunomodulatory drugs can either stimulate the immune system to fight infections more effectively or suppress it to prevent overreactions. therapies might be effective in reducing the Swelling. These studies could develop new treatment strategies that specifically modulate the dog’s Immunreaktion to alleviate symptoms and improve the animal’s well-being.

The effects of environmental factors on lymph node health are also the subject of current research. Researchers are analyzing how environmental toxins, diet, and lifestyle can affect susceptibility to lymph node Swelling. By better understanding these factors, they hope to develop preventive measures to reduce the risk of swollen lymph nodes in dogs.

Finally, the interaction between different diseases that cause lymph node Swelling is being further investigated. Complex clinical pictures can often have multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. causes, and understanding these connections can lead to more comprehensive diagnostic and treatment protocols. For example, research is being conducted on how bacterial and viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. infections in combination with autoimmune diseasesAutoimmune diseases are conditions in which the immune system mistakenly attacks the body's own cells or tissues as if they were foreign substances. Examples in dogs and cats include autoimmune hemolytic anemia and systemic lupus erythematosus. can affect the Swelling of the lymph nodes.

Häufig gestellte Fragen

What are lymph nodes and why do they swell? Lymph nodes are small, bean-shaped organs that are part of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. They filter lymph fluid and help fight infections. They swell when they produce more immune cellsImmune cells are specialized cells of the immune system that help to identify and fight pathogens and foreign substances. These include leukocytes such as lymphocytes (T cells and B cells), macrophages, and dendritic cells. to respond to infections, Inflammatory conditions, or other health problems.
Can I detect swollen lymph nodes on my dog myself? Yes, in some cases you can feel or see swollen lymph nodes, especially under the jaw, near the shoulders, or in the groin area. If you notice a Swelling, it is important to see a veterinarian for further examination.
Are swollen lymph nodes in dogs always a cause for concern? Not always. Lymph nodes can swell for various harmless reasons, such as a mild infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. However, they should not be ignored, as they can also indicate more serious health problems. A veterinary examination is advisable.
How long does it take for swollen lymph nodes to go down? This depends on the cause. With a mild infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., the Swelling may subside within a few days. For more serious conditions, it may take longer or require additional treatment.
What treatments are available for swollen lymph nodes in dogs? The therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. is based on the underlying cause. For infections, antibiotics or antiviral medications may be necessary. For Inflammatory conditions, Immunmodulatoren or corticosteroidsCorticosteroids are a class of steroid hormones that occur naturally in the body and can also be produced synthetically. They have anti-inflammatory and immunosuppressive properties and are used in veterinary medicine to treat a variety of conditions. may be used. In some cases, surgical removal is necessary.
Can swollen lymph nodes disappear on their own? Yes, if the cause is a mild infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or Inflammatory conditions, swollen lymph nodes can go away on their own once the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. has fought the cause. Nevertheless, a veterinarian should be consulted to rule out more serious causes.
How does the veterinarian diagnose swollen lymph nodes? The veterinarian will usually perform a physical examination and feel the affected lymph nodes. Further diagnostic steps may include blood tests, ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow., or biopsies to determine the exact cause of the Swelling.
Are certain dog breeds more prone to swollen lymph nodes? Some dog breeds may be more susceptible to certain diseases that cause lymph node Swelling due to genetic predispositions. Breed-typical diseases can play a role, which is why the breed’s medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. should be considered.
Can stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. in dogs lead to swollen lymph nodes? While stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can affect the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., it is rarely the direct cause of swollen lymph nodes. However, stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can exacerbate existing health problems that can lead to Swelling.
When should I take my dog to the vet if I notice swollen lymph nodes? You should see a veterinarian as soon as possible if you notice swollen lymph nodes, especially if the swelling lasts longer than a few days, the dog shows other symptoms, or its general condition worsens.