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Lumps and Bumps in or under the Skin in cats

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Lumps and bumps in or under the skin of cats are palpable thickenings or elevations that can be located either on the skin surface or under the skin. These formations can have various causes and vary in size, shape, and consistency.

Can Occur with the Following Diseases:

Basics and possible causes

Lumps and bumps can be triggered by a variety of factors. The most common causes include benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. tumors, such as lipomas or warts, which are usually harmless. However, malignantMalignant means "cancerous" and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats. tumors, such as mast cell tumors, can also be responsible for lumps. These require early 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. and treatment to prevent them from spreading.

Infections, such as bacterial abscesses, often caused by bites or scratches, can also lead to nodules. These abscesses can fill with pus and be painful. In addition, parasites such as fleas or mites can cause skin irritations that lead to nodule formation.

Allergic reactions to food, medication, or environmental factors can also affect the skin and lead to lumps or nodules. In some cases, endocrine disorders, such as hypothyroidism, can also affect skin health and lead to nodules.

Typical accompanying symptoms

Itching: Cats may frequently scratch or lick the affected areas, which indicates itching and may indicate an allergic reaction or parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. infestation.
Pain: Some lumps, especially abscesses or tumors, can be painful. The cat may react sensitively to touch or want to protect the area.
Redness and Swelling: Inflamed lumps may appear red and swollen, indicating 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 reaction 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..
Skin changes: The skin around the nodules may become discolored or scaly, which could indicate an underlying skin disease.
Behavioral changes: A cat that has pain or discomfort may withdraw, be less active, or react more aggressively.

When to visit the vet?

A visit to the veterinarian is essential if the lumps or nodules grow quickly, change their shape or color, or if they show signs of 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., such as purulentPurulent refers to pus or the production of pus, which may indicate a bacterial infection. Purulent inflammatory conditions are often painful and may have significant swelling and redness. discharge or severe redness. A veterinarian should also be consulted if the cat shows signs of discomfort or pain.

If the nodules are unusually large or occur in places that impair the cat’s normal behavior and mobility, a veterinary visit is also advisable. Early 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. and treatment are often crucial for treatment success, especially if the changes are malignantMalignant means "cancerous" and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats..

Symptom recognition for animal owners and veterinary diagnostic procedures

Pet owners should regularly examine their cat’s skin for irregularities. They can gently run their hands over the cat’s body to feel for lumps or nodules. Suspicious areas should be shown to the veterinarian.

The veterinarian will first perform a thorough clinical examination and may take a fine needle aspiration or biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. of the lump to make an accurate 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.. These procedures help determine the type of cells in the lump and distinguish between benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. and malignantMalignant means "cancerous" and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats. changes.

Additional diagnostic tests, such as blood tests, X-rays, 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., may be necessary to assess the extent of the impairment and the presence of metastasesA metastasis is a secondary tumor that originates from a primary, malignant tumor in another part of the body. Metastases indicate that cancer has spread in the body. in malignantMalignant means "cancerous" and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats. tumors.

What can pet owners do and professional therapy options

Until the veterinary visit, the pet owner should try to keep the affected area clean and dry to prevent secondary infectionA secondary infection occurs when an already weakened individual suffers an additional infection, often because the immune system is impaired by the primary infection.. Scratching or licking habits of the cat can be reduced by applying a protective collar.

It is advisable not to abruptly change the cat’s feeding or environment, as 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. could worsen the symptoms. For itching, a cooling compress can help relieve the symptoms until a specific treatment is initiated by the veterinarian.

The pet owner should make sure that the cat drinks and eats enough to support its 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.. Any changes in eating or drinking behavior should be reported to the veterinarian, as they could indicate a deterioration of the condition.

Outlook on current research

Research into lumps and bumps in or under the skin of cats is a continuously evolving field that focuses on improving diagnostic and treatment options. Scientists are investigating various aspects of these symptoms to gain a better understanding of their causes and effects. One focus of current research is on differentiating between benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. and malignantMalignant means "cancerous" and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats. skin changes. Through the development of improved diagnostic tools, such as advanced imaging techniques or molecular biological techniques, researchers hope to increase the accuracy of diagnoses and improve the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. for affected animals.

Another area of research is investigating the genetic factors that may contribute to the development of skin nodules and lumps in cats. Genetic studies aim to identify specific genes or genetic markers that are associated with an increased susceptibility to certain skin changes. In the long term, such discoveries could lead to preventive measures or targeted therapies that reduce the risk of developing skin problems in cats.

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 formation of skin changes is also being intensively investigated. Researchers are analyzing how 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. responds to certain stimuli or infections and how this could contribute to the formation of nodules and lumps. In particular, they are investigating how 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. or allergic reactions lead to the development of these symptoms. These findings could lead to new treatment approaches that target the modulation 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..

The investigation of the environmental impacts on the skin health of cats is also an important field of research. Factors such as diet, exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to environmental toxins, or 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. are being investigated for their influence on skin health and the development of lumps and nodules. By understanding these connections, veterinarians could give recommendations for lifestyle changes that reduce the risk of skin problems.

Overall, the research aims to obtain a more comprehensive picture of the causes and mechanisms that lead to lumps and bumps in or under the skin of cats. These findings should not only contribute to improving individual animal health, but also enrich general veterinary practice.

Frequently asked questions

What causes lumps and bumps in cats? Lumps and bumps in cats can be caused by a variety of factors, including infections, allergic reactions, parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. infestations, injuries, or tumors. The exact cause can often only be determined by a thorough examination by a veterinarian.
Are all lumps and bumps in cats dangerous? Not all lumps and bumps are dangerous. Some can be harmless and benign, such as fatty tumors or small cysts. However, others can be signs of more serious conditions such as cancer. A veterinarian should examine any new or unusual lump.
How are lumps and bumps diagnosed? 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. of lumps and bumps is usually made by a physical examination and possibly by additional tests such as fine needle aspiration, biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions., or imaging procedures. These tests help determine the exact cause of the lumps.
Can lumps and bumps in cats disappear on their own? Some lumps and bumps, especially those caused by allergic reactions or minor injuries, may disappear on their own. Nevertheless, it is important to have any lump examined by a veterinarian to ensure that there is no serious underlying condition.
Should I ignore lumps and bumps on my cat? No, lumps and bumps should not be ignored. Any new or changed lump should be examined by a veterinarian to ensure that it does not indicate a serious condition.
How are lumps and bumps treated in cats? Treatment depends on the cause of the lumps. BenignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors. lumps may not require treatment, while infectiousInfectious describes the ability of a pathogen to be transmitted from one individual to another and trigger an infection. It also refers to diseases caused by such pathogens. or tumorous nodules may need to be surgically removed or treated with medication. The veterinarian will recommend the best treatment option based on 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..
Can lumps in cats be painful? Yes, some lumps can be painful, especially if they are inflamed or infected. It is important to watch for signs that your cat is in pain, such as sensitivity when touching the lump or behavioral changes.
Is it normal for cats to develop more lumps as they get older? Yes, older cats are more likely to develop lumps and nodules, which are often benignBenign refers to a non-invasive, non-serious condition that is not life-threatening. In medicine, the term is often used to describe benign tumors that do not metastasize, meaning they do not form secondary tumors., such as lipomas. Nevertheless, all new or growing lumps should be examined by a veterinarian.
Can my cat’s diet affect lumps and bumps? A balanced diet can contribute to overall skin health and potentially reduce the risk of skin problems. However, certain nutrient deficiencies or allergies can promote skin changes. A change in diet may be helpful in some cases.
How can I reduce the risk of lumps and bumps in my cat? Regular veterinary check-ups, a balanced diet, and parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. control can help reduce the risk of lumps and bumps. Also, watch for changes in your cat’s behavior or skin and see a veterinarian if you notice anything unusual.

Are you unsure what is wrong with your pet? Feel free to use our symptom checker for more clarity.