title: Clinical and microscopic characteristics of canine toxic epidermal necrolysis.
abstract: Canine toxic epidermal necrosis (TEN), a rare and life-threatening cutaneous drug reaction, traditionally has been described as full-thickness devitalization of the epidermis with minimal dermal inflammation; however, few reports detail the histologic findings. We characterize the clinical features and histologic variations of 3 canine TEN patients. Clinically, irregular erythematous and purpuric macules evolved into widespread and severely painful erosions. The number of eroded mucosae varied; however, periocular and perilabial mucocutaneous junctions frequently were affected. Thirteen of 17 biopsies were evaluated. Apoptosis at multiple epidermal levels was the most common pattern of epidermal necrosis (12/13 biopsies, 92%). In contrast, full-thickness coagulation necrosis was present less often (7/13 biopsies, 52%). Lymphocytic interface dermatitis was the predominant inflammatory pattern, and intraepidermal lymphocytes, along with fewer histiocytes, were present to some degree in all samples along with lymphocytic satellitosis of apoptotic keratinocytes. The sequence of changes points to lymphocyte-mediated keratinocyte apoptosis as an early step in lesion development with subsequent variation in progression to coagulation necrosis among patients. Histopathologic changes overlapped with those reported for erythema multiforme, in contrast to traditional histologic descriptions of canine TEN. A specific algorithm for assessment of drug causality in epidermal necrolysis (ALDEN) was applied for each patient; carprofen was associated with a probable score for causality in 1 dog. Clinicians should be encouraged to take multiple biopsies in TEN suspect cases as nearly 25% of all biopsies lacked epithelium and were not diagnostic.
authors.affiliation: Department of Clinical Sciences, NC State University, College of Veterinary Medicine, Raleigh, NC, USA Center for Comparative Medicine and Translational Research, NC State University, College of Veterinary Medicine, Raleigh, NC, USA.
authors.forename: F
authors.initials: F
authors.lastname: Banovic
authors.affiliation: Department of Clinical Sciences, NC State University, College of Veterinary Medicine, Raleigh, NC, USA Center for Comparative Medicine and Translational Research, NC State University, College of Veterinary Medicine, Raleigh, NC, USA.
authors.forename: T
authors.initials: T
authors.lastname: Olivry
authors.affiliation: Department of Clinical Sciences, NC State University, College of Veterinary Medicine, Raleigh, NC, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bazzle
authors.affiliation: Department of Population Health and Pathobiology, NC State University, College of Veterinary Medicine, Raleigh, NC, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Tobias
authors.affiliation: Animal Dermatology & Allergy Clinic, Raleigh, NC, USA.
authors.forename: B
authors.initials: B
authors.lastname: Atlee
authors.affiliation: Department of Small Animal Medicine & Surgery, The University of Georgia, College of Veterinary Medicine, Athens, GA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zabel
authors.affiliation: Department of Small Animal Medicine & Surgery, The University of Georgia, College of Veterinary Medicine, Athens, GA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Hensel
authors.affiliation: Center for Comparative Medicine and Translational Research, NC State University, College of Veterinary Medicine, Raleigh, NC, USA Department of Population Health and Pathobiology, NC State University, College of Veterinary Medicine, Raleigh, NC, USA kelinder@ncsu.edu.
authors.forename: K E
authors.initials: KE
authors.lastname: Linder
mesh_terms: D000818:Animals; D017209:Apoptosis; D001706:Biopsy / Q000662:veterinary; D018450:Disease Progression; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D064420:Drug-Related Side Effects and Adverse Reactions / Q000662:veterinary; D004817:Epidermis / Q000473:pathology; D005260:Female; D009336:Necrosis / Q000662:veterinary; D013262:Stevens-Johnson Syndrome / Q000473:pathology / Q000662:veterinary*
keywords: ALDEN; Canis familiaris; carprofen; drug reaction; erythema multiforme; skin; toxic epidermal necrolysis