Skin: multisystemic eosinophilic eiptheliotropic disease in Horses (Equis) | Vetlexicon
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Skin: multisystemic eosinophilic eiptheliotropic disease

ISSN 2398-2977

Synonym(s): MEED


  • Cause: unknown.
  • Signs: exudative dermatitis over face, limbs and ventral abdomen; dullness and inappetence; weight loss, focal alopecia, sometimes with pruritus; watery diarrhea in some cases.
  • Diagnosis: biopsy of affected organs, showing infiltration of eosinophils.
  • Treatment: immunosuppressive doses of corticosteroids.
  • Prognosis: poor.

Presenting signs

  • The presenting signs vary according to the body systems involved, but commonly the skin and gastrointestinal tract are most likely to be affected.
  • Frequently reported:
    • Severe weight loss.
    • Crusting and exudative dermatitis starting at the coronary bands and oral mucosa and spreading over the face and limbs.
    • Alopecia.
    • Diarrhea.
  • Rarely, primarily respiratory signs may predominate.
  • Equine exofliative dermatitis and stomatitisis a term used to describe disease limited to the skin and oral cavity, and is probably one form of MEED.

Acute presentation

  • Acute presentation not reported; veterinary attention not usually sought until chronic signs apparent, varying between 3 weeks to 3 months.

Geographic incidence

  • No specific location.
  • Cases reported from US, UK, Canada and Australia.

Age predisposition

  • Predominantly younger horses, 4 years or younger, although ages up to 19 years have been reported.

Special risks

  • Where gastrointestinal lesions predominate, horses may develop significant hypoproteinemia   Hypoproteinemia  and hypoalbuminemia, affecting drug binding and increasing anesthetic risk.
  • Pulmonary lesions can result in pneumonia   Lung: pneumonia - bacterial   and similarly increase the risk for anesthesia.



  • Not known, but possible exaggerated Type II helper T-lymphocyte response or hypersensitivity response to nematodes have been proposed.


  • Reported in a small number of cases with concurrent lymphoma    .


  • Multisystemic eosinophilic and lymphocytic-plasmacytic infiltrates, leading to the formation of eosinophilic granulomas   Eosinophilic granuloma  in affected organs.


  • Clinical signs often present for long duration before veterinary attention sought.


Presenting problems

Client history

  • Skin lesions often started as dry, scaly cracks and inflammation at the coronary bands and mucous membrane, which then developed into widespread crusting, oozing lesions with alopecia and, in some cases, pruritus.
  • Weight loss usually significant and often diarrhea is noted too.

Clinical signs

  • Symmetrical alopecia and exudative dermatitis, particularly over the head, oral mucosa, ventral abdomen and lower limbs.
  • Poor body condition and dull demeanor.
  • May have watery diarrhea.
  • Nasal and ocular discharge and respiratory signs (chronic cough and respiratory distress) less common.
  • Peripheral lymphadenopathy   Endocrine: lymphadenopathy  (submandibular lymph nodes) may be identified.
  • Oral ulceration/stomatitis and inappetence.

Diagnostic investigation

Confirmation of diagnosis

Discriminatory diagnostic features

  • No specific diagnostic tests - diagnosis of exclusion.

Definitive diagnostic features

  • Combination of clinical signs, exclusion of other diseases and identification of characteristic lesions on biopsies of multiple organs or at post mortem examination   Post mortem examination  .

Gross autopsy findings

  • Ulceration of skin, gums, tongue and coronary bands.
  • Alopecia and exudative dermatitis.
  • Enlarged liver.
  • Enlarged and nodular pancreas.
  • Nodules within the lung parenchyma.
  • Thickened intestine and enlarged mesenteric and intestinal lymph nodes.

Histopathology findings

  • Chronic, fibrosing inflammatory reaction with lymphoplasmacytic and diffuse and focally intense eosinophilic infiltrates seen within multiple organs.
  • In some tissues, the eosinophilic infiltrate may form granulomas.

Differential diagnosis


Standard treatment

  • Systemic broad spectrum antibiotics   Therapeutics: antimicrobials  .
  • Corticosteroids: systemic dexamethasone   Dexamethasone   0.05-2 mg/kg SID.
  • The use of the antineoplastic drug hydroxyurea (20 mg/kg PO SID) has been reported with limited success.


  • Monitor response to treatment with regards to clinical signs, such as improved demeanor, reduced pruritus and resolution of diarrhea.
  • If presented with elevations in liver enzymes, these can be measured and monitored.

Subsequent management



  • Resolution of clinical signs and evidence of weight gain.
  • Abdominal ultrasound   Ultrasonography: abdomen  to monitor intestinal wall thickness.
  • Repeat radiographs   Thorax: radiography   in cases with lower respiratory tract signs.




  • Poor.
  • Affected horses are generally euthanized due to poor response to treatment, however survival and resolution of clinical signs has been reported.

Expected response to treatment

  • Resolution of clinical signs.

Reasons for treatment failure

  • Lack of response to therapy.

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Horan E M et al (2013) Pulmonary and hepatic eosinophlic granulomas and epistaxis in a horse suggestive of multi-systemic eosinophilic epitheliotropic disease. Equine Vet Educ 25 (12), 607-613 VetMedResource
  • Pucheu-Haston C M & Del Piero F (2013) Equine multi-systemic eosinophilic epitheliotropic disease. Equine Vet Educ 25 (12), 614-617 VetMedResource.
  • Singh K et al (2006) Severe pulmonary disease due to Multisystemic eosinophilic epitheliotrophic disease in a horse. Vet Pathol 43, 189-192 PubMed
  • McCue M E, Davis E G, Rush B R et al (2003) Dexamethasone for treatment of Multisystemic eosinophilic epitheliotrophic disease in a horse. JAVMA 223 (9), 1320-1323 PubMed.
  • Schumacher J, Edwards J F & Cohen N D (2000) Chronic idiopathic inflammatory bowel diseases of the horse. J Vet Intern Med 14, 258-265 PubMed.
  • La Perle K M D, Piercy R J, Long J F & Blomme E A G (1998) Multisystemic, eosinophilic, epitheliotrophic disease with intestinal lymphosarcoma in a horse. Vet Pathol 35, 144-146 PubMed.
  • Hillyer M H & Mair T S (1992) Multisystemic eosinophilic epitheliotrophic disease in a horse: attempted treatment with hydroxyurea and dexamethasone. Vet Rec 130, 392-395 PubMed.
  • Sanford S E (1989) Multisystemic eosinophilic epitheliotrophic disease in a horse. Can Vet J 30, 253-254 PubMed.
  • Nimmo Wilkie J S, Yager J A et al (1985) Chronic eosinophilic dermatitis: a manifestation of a multisystemic, eosinophilic, epitheliotropic disease in five horses. Vet Pathol 22 (4), 297-305 PubMed.