Autoimmune Skin Lesions (Eosinophilic Granuloma Complex) in Dogs

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4 min read

Key takeaways

Eosinophilic granuloma and furunculosis are skin conditions which manifest in dogs as red or yellow bumpy nodules which can be itchy or painful.

  • They result from skin inflammation triggered by hypersensitive reactions and are associated with insect bites
  • Eosinophilic granuloma may also have a genetic basis, as certain breeds are predisposed to the condition
  • Eosinophilic granuloma lesions may not cause any additional symptoms, but are sometimes painful and may result in secondary infections
  • For some patients the condition resolves itself spontaneously
  • Treatment includes topical steroids or immunosuppressive medication
  • Secondary infections are treated with antibiotics
  • Supportive therapy includes a hypoallergenic food trial, and oral medication targeting symptoms
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A closer look: Autoimmune Skin Lesions (Eosinophilic Granuloma Complex) in Dogs

Eosinophilic lesions can be categorized according to where they are located and their specific characteristics.

Eosinophilic lip ulcers are common in cats but may also occur in dogs. These are also known as rodent ulcers or indolent lip ulcers and appear as dark red or yellow, raised, round sores with clearly demarcated borders.

Eosinophilic plaques are commonly found on the hairless part of the belly. They are also usually raised and red or yellow.

Eosinophilic granulomas most commonly form lines of red or yellow nodules inside the back legs or in the mouth. They may or may not be ulcerated.

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Risk factors

Eosinophilic granuloma complex and eosinophilic furunculosis are rare in dogs.

Eosinophilic granuloma is not usually a life threatening condition, although it can lead to more severe secondary infections.

Symptoms of eosinophilic granuloma are nonspecific- rashes and irritated skin can imply a number of more common conditions, some more severe than others. Any dog with these symptoms requires prompt medical intervention to assure proper diagnosis and treatment.

Siberian Huskies and Cavalier King Charles Spaniels may have a genetic predisposition to granuloma complex.

Possible causes

The cause of an eosinophilic granuloma is not always clear. Both eosinophilic granuloma complex and furunculosis are associated with hypersensitive reactions to insect bites, although parasites, pollens, and foods are also suspected. Some breeds of dog appear more susceptible to granuloma than others, suggesting that there is a genetic predisposition to the condition.

Main symptoms

Symptoms of eosinophilic granuloma and furunculosis develop quickly. Skin changes associated with this condition are commonly a reddish or yellowish color, and are usually concentrated about the nose and muzzle. The lesions can swell, and be itchy or painful. If a nodule breaks it can produce discharge or crust over.

Testing and diagnosis

A vet presented with symptoms of granuloma complex performs a physical examination and series of blood tests. A biopsy is necessary to confirm the diagnosis since other types of potentially more serious skin masses are more common.

Steps to Recovery

As these conditions are most commonly associated with hypersensitive reactions, common treatments include oral immunosuppressives or steroids. Supportive therapies such as a hypoallergenic food trial or other medication may be indicated. Hypersensitivity reactions are commonly triggered by plastic food and water bowls, so changing to metal, glass, or ceramic may be beneficial.

Surgical excision of small lesions may be necessary, or antibiotics if there is a secondary infection.

The prognosis is good for furunculosis, and more variable for lesions seen with eosinophilic granuloma complex as it is not always responsive to steroid treatment.

If the condition recurs it may suggest that the dog is allergic to something which they have continued exposure to.


Insect control may help prevent both eosinophilic granuloma and furunculosis. Neither condition is contagious.

Are Autoimmune Skin Lesions (Eosinophilic Granuloma Complex) in Dogs common?

These conditions are rare in dogs

Typical Treatment

  • Steroids
  • Antibiotics
  • Immunosuppressives
  • Surgery
  • Supportive care

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