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Immunopathological study on equine insect hypersensitivity ("kasen") in Japan
T Kurotaki1, K Narayama, T Oyamada
1Department of Veterinary Pathology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan.
Journal of Comparative Pathology
|February 1, 1994
Summary
Equine kasen, a chronic summer dermatitis, involves skin lesions with hyperkeratosis and increased immune cells. Histopathology reveals it as a type I and type IV allergic reaction, similar to Queensland and sweet itch.
Area of Science:
- Veterinary Dermatology
- Equine Pathology
Background:
- Equine kasen is a chronic summer dermatitis affecting horses.
- Understanding its histopathological features is crucial for diagnosis and treatment.
Purpose of the Study:
- To histopathologically classify skin lesions of equine kasen into distinct stages.
- To identify characteristic cellular and ultrastructural changes associated with kasen.
- To compare kasen with similar equine dermatitides like Queensland itch and sweet itch.
Main Methods:
- Biopsies of kasen skin lesions were collected from May to October.
- Lesions were histopathologically classified into initial (Group I), developing (Group II), and regressing (Group III) stages.
- Immunohistochemistry (MHC class II) and ultrastructural analysis (Birbeck granules) were performed.
Main Results:
- Characteristic lesions included hyperkeratosis, increased T-lymphocytes and Langerhans cells (MHC class II positive) at the epidermo-dermal junction, dermal edema, and eosinophilic/mast cell perivascular infiltration.
- Birbeck granules were observed in Langerhans cells, particularly in the developing stage.
- Lesion severity was most pronounced in the developing stage (Group II).
Conclusions:
- Equine kasen exhibits histological features consistent with type I and type IV allergic dermatitis.
- The findings support the similarity of kasen to Queensland itch and sweet itch.
- Histopathological staging provides insight into the progression of kasen lesions.