JPC SYSTEMIC PATHOLOGY
INTEGUMENTARY SYSTEM
August 2019
I-B01

Signalment (JPC# 1313232):  Ox

HISTORY:  This ox had raised, alopecic skin lesions covered by thick crusts

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Diffusely, the mildly hyperplastic and focally ulcerated epidermis is overlain by a 1 mm thick serocellular crust that entraps fragmented hair shafts and sebaceous glands.  The crust is composed of laminations of abundant orthokeratotic and parakeratotic keratin debris (hyperkeratosis), fibrin, numerous viable and degenerate neutrophils, and eosinophilic cellular and karyorrhectic debris (intracorneal pustules). Superficially within the crust there are numerous 1-2 um, paired coccoid bodies (zoospores) haphazardly arranged in rows and forming long, branching filaments, admixed with large colonies of 2 um diameter coccoid zoospores. Diffusely the underlying epidermis is mildly hyperplastic, with acanthosis and short rete peg formation. There is focal ulceration of the epidermis, and the subjacent dermis contains hemorrhage, fibrin, and edema.  Multifocally within the superficial dermis, surrounding hair follicles, there are reactive fibroblasts and low numbers of macrophages, neutrophils, lymphocytes, and plasma cells admixed with variable amounts of hemorrhage and multifocal mineralization.  Multifocally, superficial dermal vessels are lined by hypertrophied endothelium and are occasionally occluded by dense fibrillar to beaded, eosinophilic material (fibrin thrombi) which rarely contain endothelial-lined slit-like channels (recanalization).

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Epidermitis, suppurative, exudative, and proliferative, chronic, diffuse, severe, with marked orthokeratotic and parakeratotic hyperkeratosis, intracorneal pustules, ulceration, fibrin thrombi, and superficial coccoid zoospores and branching filaments, etiology consistent with Dermatophilus congolensis, breed not specified, bovine.

ETIOLOGIC DIAGNOSIS:  Cutaneous dermatophilosis

CAUSE:  Dermatophilus congolensis

SYNONYMS:  Cutaneous streptothricosis, rain scald; rain rot; lumpy wool; strawberry foot rot; cutaneous actinomycosis; Kirchi; Gasin-Gishu; Senkobo disease; Drodo-Boka; Savi; Ambarr-Madow; (“mycotic dermatitis” is a misnomer)

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

Proliferative/Hyperkeratotic Skin Lesions in Cattle:

COMPARATIVE PATHOLOGY:

References:

  1. AuFox EE, Frank LA, et al. The prevalence of Dermatophilus congolensis in horses with pastern dermatitis usuing PCR to diagnose infection in a population of horses in Southern USA. Vet Dermatol. 2018; 29(5):435.
  2. Hargis AM, Myers S. The Integument. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:1073-1074.
  3. Mauldin EA, Peters-Kennedy J. Integumentary System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. Vol. 1. Louis, MO: Elsevier; 2016: 632-634.
  4. Nemeth NM, Ruder MG, Gerhold RW, Brown JD, et al. Demodectic mange, dermatophilosis, and other parasitic and bacterial dermatologic diseases in free-ranging white-tailed deer (Odocoileus virginianus) in the United States from 1975 to 2012. Vet Pathol. 2014;51(3): 633-640.


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