Eosinophilic nodular to diffuse dermatitis



Canine acute eosinophilic dermatitis with edema (Wells like syndrome)

Initialism: CAEDE

Clinical signs: Generalised nodules, macules and erythema with edema involving the whole body but particularly noticeable on the abdominal skin.

Dermatopathology: The lesion is a severe nodular to diffuse dermatitis dominated by eosinophils and edema, and with flame figures and collagen degeneration.

Pathogenesis: There is a strong causative relationship with gastrointestinal disease or administration of drugs. Those with gastrointestinal disease, including pancreatitis, adverse reaction to food and idiopathic "inflammatory bowel disease", have resolution of skin lesions in about three weeks after onset. Gastrointestinal disease usually resolves after five days. Those with adverse drug reaction respond to withdrawal, antihistamines and corticosteroids. It is believed to be a type I hypersensitivity reaction. There is a report of this occurring with T cell lymphoma.

Differential diagnosis: acute sterile neutrophilic dermatitis (sweets syndrome)


Cain CL, Bradley CW 2nd, Mauldin EA. Clinical and histologic features of acute-onset erythroderma in dogs with gastrointestinal disease: 18 cases (2005-2015). J Am Vet Med Assoc. 2017; 251: 1439-1449.

Mauldin EA. Canine Acute Eosinophilic Dermatitis with Edema (Wells-Like Syndrome). Vet Clinics North America 2019; 49: 45-51

Mauldin EA, Palmeiro BS, Goldschmidt MH, Morris DO. Comparison of clinical history and dermatologic findings in 29 dogs with severe eosinophilic dermatitis: a retrospective analysis. Veterinary Dermatology 2006; 17, 338-347.


Sterile eosinophilic pustulosis

General comments

Clinical signs

This disease usually does not affect the face or head. Abdominal lesions are described, and it is a pruritic disease. Pustules, collarettes and papules are found.


The original description of this disease describes a combination of intraepidermal eosinophilic pustules, mural eosinophilic folliculitis and furunculosis. Other reported suggest nodules of eosinophils in the dermis not involving the follicles. The intraepidermal and follicular pustules may have acantholytic cells in them. There is a suggestion that intraepidermal pustules are not always present.

Differential diagnosis

Eosinophilic furunculosis of the face

Pemphigus foleaceous


It appears that this condition may be a combination of eosinophilic vesiculopustular disease, nodular eosinophilic disease or eosinophilic furunculosis. It does not have to have all 3.

Scott DW. Sterile eosinophilic pustulosis in dog and man: Comparative aspects.


Canine pallisading dermatitis and pannuculitis (granuloma granuloma)

histiocytes palisade along degenerate collagen.

Differential diagnoses include

  1. sterile granuloma and pyogranuloma syndrome,
  2. reactive histiocytosis,
  3. cutaneous xanthoma,
  4. canine sarcoidosis,
  5. foreign body reactions,
  6. reactive fibrohistiocytic nodules,
  7. sterile granulomatous dermatitis and lymphadenitis (juvenile and adult-onset cellulitis)


Lund et al (2021) reported on 36 cases. All cells were IBA1 and CD204 +ve. 32 had strong or moderate degenerate collagen and 3 had mild. , 31 had focal nodules and 19 had lesions restricted to face and head. 5 had many eosinophils.


Lund M, Mauldin EA, Radaelli E, Bradley CW. Palisading granulomatous dermatitis and panniculitis (palisading granuloma) of dogs. Vet Pathol. 2021; 58: 1091-1099.



Sweets syndrome (acute febrile neutrophilic dermatitis)



Mellor PJ, Roulois AJ, Day MJ, Blacklaws BA, Knivett SJ, Herrtage ME. 2005 Neutrophilic dermatitis and immune-mediated haematological disorders in a dog: suspected adverse reaction to carprofen. J Small Anim Pract. 2005 May;46(5):237-42.

Pyoderma gangrenosum

            Nodular disease that ruptures to for large craters. Neutrophilic and non-infectious.
Deborah L. Simpson*, Gregory G. Burton† and Lydia E. Hambrook‡ (2013)
Canine pyoderma gangrenosum: a case series of two dogs Vet Derm 2013 24:
Background – Pyoderma gangrenosum (PG) is a rare disease, which, to the best of the authors’ knowledge, has been the subject of only one case report in the peer-reviewed veterinary literature.
Hypothesis/Objectives – To describe the history, clinical signs, diagnostic findings and treatment outcome in two cases of canine PG.
Animals – Two client-owned dogs presented to a private veterinary referral practice between 2008 and 2010 who received a diagnosis of PG by specialist veterinary dermatologists.
Methods – Medical records were analysed to retrieve relevant information.
Results – Both dogs were treated with prednisolone; this was combined with ciclosporin in case 1 and azathioprine in case 2. Case 2 had a more complete response of lesions to treatment and a longer survival time after diagnosis (763 days) than case 1 (81 days).
Conclusions and clinical importance – Pyoderma gangrenosum is a rare disease distinguished by rapid progression of painful, necrolytic, cutaneous ulcers with irregular, violaceous undermined borders. Azathioprine with glucocorticoids may lead to a better outcome than ciclosporin and glucocorticoids (currently the first-line treatment in humans and the only reported treatment in dogs).

Neutrophilic immunological vasculitis

Toxic shock syndrome

Must have systemically ill, febrile, hypoalbuminemic or otherwise abnormal on routine bloodwork

Often a history of shampooing within a week of signs.

Neutrophilic nodular to diffuse dermatitis with edema.

Epidermis has ballooning degeneration, parakeratosis and basal hyperplasia mimicing superficial necrotizing dermatitis.

Epidermis and infundibulum have single cell death with neutrophilic satellitosis

Staphylococcal TSS

Superficial disease beginning at the epidermis and causing necrosis with neutrophils

Streptococcal TSS

Necrotizing fasciitis

DDX is acute febrile neutrophilic dermatitis (sweets)

Sterile pustular erythroderma of miniature schnauzer (aka superficial suppurative necrolytic dermatitis

A case of superficial suppurative necrolytic dermatitis of
miniature schnauzers with identification of a causative
agent using patch testing
Nobuo Murayama*, Kuniaki Midorikawa† and
Masahiko Nagata*
Murayama N1, Midorikawa K, Nagata M. A case of superficial suppurative necrolytic dermatitis of miniature schnauzers with identification of a causative agent using patch testing. Vet Dermatol. 2008; 19: 395-399.
A 9-year-old, castrated male, miniature schnauzer presented with malaise, anorexia, fever and severe inflammatory skin lesions on the dorsum, thighs and pinnae. The lesions developed 2 days after bathing with a commercial shampoo. Histopathological examination of skin samples revealed neutrophilic exocytosis, parakeratosis, epidermal hyperplasia and neutrophilic infiltration in the superficial dermis. Skin lesions resolved completely after 14 days of treatment with prednisolone and ofloxacin. Patch testing performed on the patient and a clinically healthy dog showed erythema at the site exposed to the culprit shampoo 48 h later only on the patient. Histopathological findings of the erythematous reaction were similar to those of the spontaneous skin lesions. Based on these findings, the dog was diagnosed with superficial suppurative necrolytic dermatitis of miniature schnauzers. The patch test results suggested that contact dermatitis to a commercial shampoo played a role in the pathogenesis of this disease.


Pyogranulomatous nodular to diffuse dermatitis



Neospora caninum

Neosporiosis is uncommon in dogs and infection of the skin as a primary disease is not reported. It is reported as a cutaneous manifestation of systemic disease. Dogs are usually in an altered immunocompetent state. Occasionally, immunocompetent dogs are affected.

The gross lesions are 2 to 10 cm nodules that often rupture and release serosanguinous fluid. They are in the dermis and panniculus anywhere on the body.

Histologically, the lesions are nodular, in the dermis and panniculus and frequently have a necrotic center. Neutrophils and macrophages surround these necrotic foci. Organisms are usually visible on routine sections and immunohistochemistry is helpful for better identification.


Decôme M, Martin E, Bau-Gaudreault L, O'Toole E. Systemic disseminated Neospora caninum infection with cutaneous lesions as the initial clinical presentation in a dog. Can Vet J. 2019; 60: 1177-1181.



Sterile Granulomatous Dermatitis and Lymphadenitis (Juvenile Cellulitis)

Initialism: SGDL

Clinical signs

Juvenile Cellulitis is also known as puppy strangles. It usually affects puppies from 2 weeks to 4 months. It is now recognised in adult dogs.

It typically affects animals on the muzzle, periocular skin and pinnae. Other locations on the body sometimes are affected, including the feet and perianal and genital regions. Draining lymph nodes may be affected. In some litters, multiple puppies can be affected.

Breeds affected in puppies include Golden retriever, dachshund, Labrador retriever and Gordon setter. In adults, have a niece, Australian Shepherd, Irish setter, Dachshund, bichon frise and Maltese dogs were overrepresented.


This is a granulomatous to pyogranulomatous dermatitis. The lesions are between the follicles, are present at the superficial dermis and can extend into the subcutis.

Individual lesions have clusters of neutrophils centrally and a surrounding layer of epithelioid macrophages. No agents are found with special stains, typically PAS, Gram and acid-fast stains. There may be a folliculitis furunculosis if there is secondary bacterial infection. The pyogranulomatous lesions are not consistently targeting of hair follicles.


The underlying cause of this disease is not known. A hereditary basis is assumed in puppies when multiple members of a litter are affected. No infectious organisms are recognized. It is presumed to be an excessive immunological response to some unknown antigen. Response to corticosteroids or other immune modulating agents suggests an immunological basis.

Inga A, Griffeth GC, Drobatz KJ, Goldschmidt KH, Mauldin EA. Sterile granulomatous dermatitis and lymphadenitis (juvenile cellulitis) in adult dogs: a retrospective analysis of 90 cases (2004-2018). Vet Dermatol. 2020; 31: 219-e47