Erythema multiforme

From Dog
Erythema multiforme secondary to epitheliotropic T-cell lymphoma in a Maltese[1]
Erythema multiforme in a dog due to food allergy[2]

Erythema multiforme (EM) is a immune-mediated disease paraneoplastic disease of dogs involving T-cell attack on nonself-epithelial and mucocutaneous antigens thought to be associated with reactions to viral, bacterial and various drugs[1][3]. It has been observed as a prelude to thymoma[4], splenic sarcoma[5] and lymphoma in dogs.

This disease, in its various forms, is clinically difficult to distinguish from pemphigus vulgaris and epitheliotropic T-cell lymphoma[6], and can occur days to months after exposure to antigenic stimuli[7]. The spectrum of presentations, which are difficult to distinguish within themselves, include erythema multiforme minor, erythema multiforme major, Stevens-Johnson syndrome and toxic epidermal necrolysis[8].

Although EM has been associated with many purported triggering factors, a true cause-and-effect relationship is rarely documented[9]. Elimination of the trigger factors are important in the diagnosis and treatment of this disease, but in up to 20% of canine cases, identification of the cause has not been possible.

Clinically affected dogs often present with stomatitis and numerous papular erythematous skin eruptions in the axillae, groin, mucocutaneous junctions and pinnae.

This disease is characterized by ulcerative stomatitis with no significant or only minor abnormalities on haematology and serum biochemistry panels and production of T-cell clones against particular epithelial keratinocytes in the skin and mucous membranes. Histologically, EM usually shows individual keratinocyte apoptosis associated with lymphocyte exocytosis in all layers of the epidermis.

Various diseases have been associated with EM, including:

A differential diagnosis would include epitheliotropic T-cell lymphoma, ear margin seborrhea, chemical and thermal burns, superficial necrolytic dermatitis, dermatomyositis and sepsis.

Treatment of most cases include use of emollient skin creams, oral azathioprine, prednisolone and with dietary allergies, a hypoallergenic diet.


  1. 1.0 1.1 Wikipedia
  2. Scott, DW (2008) Erythema multiforme in a dog caused by a commercial nutraceutical product. JVCS 1(3):16-21
  3. Freedberg IM et al (2003) Fitzpatrick’s Dermatology in General Medicine, 6th ed. McGraw-Hill, New York. pp:543-557
  4. Tepper LC et al (2011) Diagnosis of erythema multiforme associated with thymoma in a dog and treated with thymectomy. J Am Anim Hosp Assoc 47(2):e19-e25
  5. Elmore SA et al' (2005) Paraneoplastic pemphigus in a dog with splenic sarcoma. Vet Pathol 42(1):88-91
  6. Nemec A et al (2011) Erythema multiforme and epitheliotropic T-cell lymphoma in the oral cavity of dogs: 1989 to 2009. J Small Anim Pract 53(8):445-452
  7. Hanley CS et al (2005) Erythema multiforme in a spotted hyena (Crocuta crocuta). J Zoo Wildl Med 36(3):515-519
  8. Scott DW et al (2001) Muller & Kirk’s Small Animal Dermatology, 6th ed. W. B. Saunders, Philadelphia. pp:729-740
  9. Scott DW & Miller WH (1999) Erythema multiforme in dogs and cats: literature review and case material from the Cornell University College of Veterinary Medicine (1988-1996). Vet Dermatol 10:297-309
  10. Bowman DD et al (2010) Hookworms of dogs and cats as agents of cutaneous larva migrans. Trends Parasitol 26(4):162-167
  11. Woldemeskel M et al (2011) Canine parvovirus-2b-associated erythema multiforme in a litter of English Setter dogs. J Vet Diagn Invest 23(3):576-580
  12. Favrot C et al (2000) Parvovirus infection of keratinocytes as a cause of canine erythema multiforme. Vet Pathol 37(6):647-649
  13. Itoh T et al (2006) Erythema multiforme possibly triggered by food substances in a dog. J Vet Med Sci 68(8):869-871
  14. Nuttall TJ & Malham T (2004) Successful intravenous human immunoglobulin treatment of drug-induced Stevens-Johnson syndrome in a dog. J Small Anim Pract 45(7):357-361
  15. Rosenbaum MR & Kerlin RL (1995) Erythema multiforme major and disseminated intravascular coagulation in a dog following application of a d-limonene-based insecticidal dip. J Am Vet Med Assoc 207(10):1315-1319