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Panniculitis in Dogs - Causes, Symptoms and Treatment

Cristina Pascual
By Cristina Pascual, Veterinaria. Updated: January 29, 2024
Panniculitis in Dogs - Causes, Symptoms and Treatment

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Panniculitis is an inflammatory process that affects adipose tissue, the tissue we associate with body fat. It has multiple causes, both infectious and non-infectious. There are also many cases of idiopathic panniculitis in dogs where the etiology is unknown. The main clinical sign associated with panniculitis in dogs is the presence of subcutaneous nodules of variable consistency. They can become ulcerated and fistulize. Treatment can be surgical or pharmacological, depending on the specific type of panniculitis and the number of nodules that present.

In this AnimalWised article, we look at panniculitis in dogs, specifically its causes, symptoms and treatment. We also look at the different types of canine panniculitis according to area affected, infiltrate and more.


  1. What is panniculitis in dogs?
  2. Types of panniculitis in dogs
  3. Causes of panniculitis in dogs
  4. Symptoms of panniculitis in dogs
  5. Diagnosis of panniculitis in dogs
  6. Treatment of panniculitis in dogs

What is panniculitis in dogs?

Panniculitis is the inflammation of the panniculus adiposus, a fatty layer of subcutaneous adipose tissue. In many cases, this inflammation of the fat is produced by the extension of dermis inflammation (dermatitis). This is known as celulitis.

For more information on canine skin inflammation, take a look at our article on atopic dermatitis in dogs.

Types of panniculitis in dogs

Panniculitis can be classified according to the type of inflammatory infiltrate, i.e. the material which inflames the tissues or cells. The distribution of the lesion in the adipose pad and the etiology also factor in the types of panniculitis in dogs.

Types of panniculitis depending on the inflammatory infiltrate:

  • Pyogranulomatous panniculitis: neutrophils and macrophages predominate. It is the most frequent.
  • Neutrophilic panniculitis: neutrophils predominate.
  • Eosinophilic panniculitis: eosinophils predominate.
  • Lymphocytic panniculitis: lymphocytes predominate.

Types of panniculitis depending on the distribution of the lesion in the panniculus:

  • Lobular panniculitis: the inflammation is located in the lobes of adipose tissue.
  • Septal panniculitis: the inflammation is located in the interlobular connective tissue.
  • Diffuse panniculitis: inflammation affects both compartments (both the lobes and the septa). It is the most common type in dogs.

Types of panniculitis according to etiology:

  • Infectious panniculitis: produced mainly by bacteria and fungi. For a more general overview, take a look at our guide to fungal infection in dogs.
  • Non-infectious panniculitis: caused by trauma, burns, vitamin E deficiency, pancreatitis, immune-mediated diseases, reaction to foreign bodies, vaccines or injections.
  • Sterile panniculitis: is idiopathic, i.e. of unknown origin. Also known as sterile nodular panniculitis or SNP.

Causes of panniculitis in dogs

The main causes of panniculitis in dogs are the following:

  • Infectious agents: mainly bacteria (Staphylococcus pseudintermedius, Mycobacterium, Pseudomonas, Proteus, etc.) and fungi (Microsporum and Trichophyton).
  • Trauma and extensive burns: reduce blood supply to the subcutaneous tissue, leading to focal ischemia.
  • Immune-mediated diseases: in these cases, panniculitis usually appears associated with immune-mediated vascular diseases, such as systemic lupus erythematosus.
  • Pancreatitis: occurs as a result of liquefaction necrosis of the subcutaneous tissue. Find out the underlying causes of pancreatitis in dogs for more information.
  • Nutritional: due to vitamin E deficiency, although this cause is usually more frequent in cats with diets rich in fish oil.
  • Reaction to foreign bodies, vaccines or injections: although they can cause panniculitis in dogs, they tend to be more frequent in cats.
  • Idiopathic: of unknown etiology, such as sterile nodular panniculitis or sterile German Shepherd pedal panniculitis.

Symptoms of panniculitis in dogs

The clinical signs that can be seen in dogs with panniculitis are as follows:

  • Presence of one or more subcutaneous nodules: they can be deep and fluctuating in size, and painful or painless. The nodules may be firm and well circumscribed or they may be soft and poorly defined. These nodules often ulcerate and fistulate to the outside. When this happens they secrete a greasy, bloody fluid. Normally the nodules are usually found on the chest of the animal, although they can appear in other areas such as the abdomen, chest or head.

  • General clinical signs: include anorexia, lethargy or depression, especially in animals with multiple lesions. If your dog is losing weight, despite inflammation, it could be due to a number of reasons. Take a look at our article on why your dog is losing a lot of weight to learn more.

Diagnosis of panniculitis in dogs

A differential diagnosis will be required to diagnose panniculitis in dogs. This means taking into account the dog's medical history, a physical examination, assessment of clinical signs and more. In terms of clinical signs, we will need to to look out for subcutaneous neoplasms, abscesses, cysts and granulomas, among others.

The diagnosis of panniculitis should be based on the following assessments:

  • General examination: deep subcutaneous nodules, often ulcerated or fistulized, may be palpated during the examination. Although the entire surface of the animal should be palpated, it is important to pay special attention to the body since the nodules are usually concentrated in this area.
  • Blood tests (hemogram and biochemical profile): in case of infection it will be common to find leukocytosis (increase in white blood cells) and in case of pancreatitis we will find an increase in pancreatic lipase (PLI). Find out more on how to understand a dog's blood test.
  • Fine Needle Puncture (FAP) for cytology: since pyogranulomatous panniculitis is the most frequent in dogs, lipid vacuoles are usually observed in cytologies along with macrophages that contain fat droplets inside. In the case of septic panniculitis, we can observe bacteria or fungi. However, there are studies that suggest cytologies can lead to the diagnostic error of classifying these nodules as neoplasms, especially when they are firm nodules. Therefore, it is important to perform a biopsy to reach a definitive and accurate diagnosis.
  • Biopsy: allows analysis of the tissue by pathological anatomy and reaches a definitive diagnosis.
  • Culture and antibiogram: in case of infectious panniculitis, it will be important to perform an in vitro culture to identify the causative agent. Subsequently, an antibiogram should be performed in order to determine which antibiotics are effective against the etiologic agent of panniculitis.

Treatment of panniculitis in dogs

Treatment will depend on the type of panniculitis and the number of nodules that the animal presents:

  • Surgery: surgical removal of the nodules is usually the most common treatment of solitary nodules, as it usually provides good results.
  • Immunosuppressive treatment: when the animal has multiple nodules, treatment with glucocorticoids at immunosuppressive doses, such as dexamethasone or prednisone, is usually chosen. Glucocorticoids can be administered orally, topically, or intralesionally. Some dogs may also respond to other immunosuppressive drugs such as cyclosporine.
  • Antibiotic treatment: in case of infectious panniculitis, it will be necessary to resort to antibacterial or antifungal treatments. In order to avoid antibiotic resistance, antibiotic therapy with an effective antibiotic against the microorganism causing the panniculitis should be instituted. For this, it is essential to include a culture and an antibiogram as part of the diagnostic protocol.

Most animals achieve a prolonged or permanent remission of the inflammatory process. However, in some cases the lesions may reappear, requiring long-term glucocorticoid therapy.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Panniculitis in Dogs - Causes, Symptoms and Treatment, we recommend you visit our Skin problems category.

  • Contreary, C. L., Outerbridge, C. A., & Affolter, V.K. (2015). Canine sterile nodular panniculitis: a retrospective study of 39 dogs. Veterinary Dermatolology, 26, 451
  • Harvey, R. G., & Mckeever, P. J. (2001). Illustrated manual of skin diseases in dogs and cats. Grass Edicions.
  • Machicote, G. (2014). Atlas of Canine and Feline Dermatology. Servet.
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Panniculitis in Dogs - Causes, Symptoms and Treatment