JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

November 2016

I-P07

 

Slide A
Signalment (JPC 1368758):  3-year-old German shepherd dog

HISTORY:  Euthanized because of generalized chronic dermatitis

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Multifocally within the dermis there is perifolliculitis composed of moderate numbers of lymphocytes, plasma cells, macrophages, and fewer neutrophils.  Inflammatory cells occasionally infiltrate and partially disrupt follicular epithelium (interface mural folliculitis), and there is hydropic degeneration and single-cell necrosis of follicular epithelial cells.  Filling and expanding follicles are segments of arthropods, up to 40 um in diameter and 200 um in length, with a thin, eosinophilic, chitinous exoskeleton, short jointed appendages, a hemocoel, striated muscle, and digestive and reproductive tracts.  There are few pigment-laden melanomacrophages surrounding follicles (pigmentary incontinence).  Diffusely, there is moderate follicular and epidermal hyperplasia with orthokeratotic hyperkeratosis.  Apocrine glands are mildly ectatic, occasionally hyperplastic and filled with varying amounts necrotic debris.

Tongue:  No significant lesions.

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Dermatitis, perifolliculitis, and interface mural folliculitis, lymphoplasmacytic and histiocytic, chronic, multifocal, moderate, with epidermal and follicular hyperplasia, hyperkeratosis, and intrafollicular mites, etiology consistent with Demodex canis, German shepherd dog, canine.

ETIOLOGIC DIAGNOSIS:  Follicular demodicosis

CAUSE:  Demodex canis

CONDITION:  Demodectic mange

CONDITION SYNONYMS:  Red mange; follicular mange

Slide B
Signalment (JPC 1051577):  A pig

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  Haired skin and subcutis:  Diffusely, hair follicles are markedly ectatic, up to 2‑3 mm in diameter, and lined by degenerate epithelial cells.  These follicles are expanded and filled with numerous elongate mites that are 40 um wide and 150-200 um long, with a thin, eosinophilic, chitinous exoskeleton, short jointed appendages, a hemocoel, striated muscle, and digestive and reproductive tracts.  Multifocally surrounding hair follicles, sebaceous glands, and blood vessels are few lymphocytes, plasma cells, macrophages, and eosinophils.  Multifocally, apocrine glands are mildly ectatic and filled with numerous neutrophils.  Diffusely, the epidermis and hair shafts are absent (due to slaughter scalding and processing).

MORPHOLOGIC DIAGNOSIS:  Haired skin and subcutis:  Follicular ectasia, multifocal, marked, with periadnexal and perifollicular lymphoplasmacytic and eosinophilic dermatitis, moderate neutrophilic apocrine adenitis, and numerous intrafollicular mites, etiology consistent with Demodex phylloides, breed not specified, porcine.

ETIOLOGIC DIAGNOSIS:  Follicular demodicosis

CAUSE:  Demodex phylloides

CONDITION:  Demodectic mange

CONDITION SYNONYMS:  Red mange; follicular mange

GENERAL DISCUSSION: 

LIFE CYCLE

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS:

Localized form:

Generalized form:

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

DIFFERENTIAL DIAGNOSIS:

For gross lesions:

For histologic lesions:

COMPARATIVE PATHOLOGY:

References: 

  1. Ferrer L, Ravera I, Silbermayr K. Immunology and pathogenesis of canine demodicosis.  Vet Dermatol 2014;25(5)427-e65.
  2. Ferriera D, Sastre N, Ravera I, Alted L, Francino O, Bardagi M, Ferrer L. Identification of a third feline Demodex species through partial sequencing of the 16S rDNA and frequency of Demodex species in 74 cats using a PCR assay.  Vet Dermatol. 2015;26(4)239-e53.
  3. Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Skin diseases of the dog and cat. 2nd ed. Oxford, UK:Blackwell Science; 2005:222-225, 442-449.
  4. Maudlin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: 678-682.  
  5. Milosevic MA, Frank LA, Brahmbhatt RA, Kania SA. PCR amplification and DNA sequencing of Demodex injai from otic secretions of a dog.  Vet Dermatol.  2013;24(2):286-e66.
  6. Moriello KA, Newbury S, Steinberg H. Five observations of a third morphologically distinct feline Demodex  Vet Dermatol.  2013;24(4):460-462.
  7. Nemeth NM, Ruder MG, Gerhold RW, Brown JD, Munk BA, Oesterle PT, Kubiski SV, Keel MK. Demodectic mange, dermatophilosis, and other parasitic and bacterial dermatologic diseases in free-ranging white-tailed deer (Odocoileus virginianus) in the United States from 1975-2012.  Vet Pathol.  2014;51(3):633-640.
  8. Percy DH, Barthold SW. Pathology of Laboratory Rodents & Rabbits. 2nd ed. Ames, IA:Iowa State University Press; 2001:76, 145-146, 184, 203, 228.
  9. Ravera I, Alted L, Francino O, Sanchez A, Roldan W, Villanueva S, Bardagi M, Ferrer L. Small demodex populations colonize most parts of the skin of healthy dogs.  Vet Dermatol.  2013;24(1):168-172.
  10. Salvadori C, Formenti N, Trogu T, Lanfranchi P, Papini R, Poli A. Demodicosis in Chamois (Rupicapra rupicapra rupicapra) in the Italian Alps, 2013-2014.  J Wildlife Diseases.  2016;52(2)433-435.
  11. Scott DW, Miller WH, Griffin CE. Muller & Kirk’s Small Animal Dermatology. 6­­th ed. Philadelphia, PA:WB Saunders Co; 2001:457-470, 474-476.
  12. Smith PC, Zeiss CJ, Beck AP, Scholz JA. Demodex musculi infestation in genetically immunomodulated mice.  Comp Med.  2016;66(4)278-285.
  13. Straw BE, D’Allaire S, Mengeling WL, Taylor DJ. Diseases of Swine. 8th ed. Ames, IA:Iowa State University Press; 1999:675-676.


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