Animal skin diseases may result from various etiological factors. Some of these may act directly upon the skin itself, or indirectly via the blood, the lymph or the nervous system. Many internal pathological conditions may be the primary cause of various skin manifestations thus explaining why skin diseases of animals have always been studied in internal medicine

Kral, Frank

English

Iowa State University Computer Science Technical Reports

Etiology and Classification of Animal Dermatoses

Animal skin diseases may result from various etiological factors. Some of these may act directly upon the skin itself, or indirectly via the blood, the lymph or the nervous system. Many internal pathological conditions may be the primary cause of various skin manifestations thus explaining why skin diseases of animals have always been studied in internal medicine.</p

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Etiology and Classification of Animal Dernlatoses Frank Kral, V.M.D., M.V.D., (h.c.), doc. habil. A NIMAL SKIN DISEASES may re-sult from various etiological fac-tors. Some of these may act directly upon the skin itself, or indirectly via the blood, the lymph or the nervous system. Many internal pathological conditions may be the primary cause of various skin mani-festations thus explaining why skin di-seases of animals have always been stud-ied in internal medicine. The rational treatment of any disease requires a correct diagnosis. Particularly in skin diseases, it is very important to establish not only symptomatic diagnosis according to the appearance of the skin lesions, but to find out the causative or predisposing agent and to establish the etiologic diagnosis. The fundamentals in an etiologic diagnosis of cutaneous dis-orders should be based upon the knowl-edge of direct or indirect causes found from an adequate history and a complete examination not only of the skin itself but also of the internal condition. Spe-cific diagnostic methods, including ultra-violet rays, biologic tests, microscopic examination of skin scrapings, blood tests, bacteriologic investigation, tissue studies and even experimental animal inoculation may be an essential aid to the etiologic diagnosis of various cu-taneous disorders. The classification of animal skin dis-eases may be approached from several standpoints. Grouping may be based upon clinical cutaneous symptoms, path-ologic-anatomic changes, functional dis-orders of the skin, or upon the origin of the skin lesions. No one system is able to include all the changes of the integu-ment. In many animal skin conditions, we still do not know the exact pathology, the basic functional disorders, and in Dr. Kral is professor of Veterinary Medicine, School of Veterinary Medicine, University of Penn. Issue 2, 1958-59 many of them we do not know the pri-mary cause. For practical purposes, therefore, the systems of classification are used in combination, or in supple-ment to each other. Skin Inflammation. Dermatitis. Skin inflammations represent a reaction in the form of specific cutaneous changes in response to some potentially destructive agents of the skin. The skin primarily must evidence some degenerative or even necrotic changes, which secondarily pro-duces a healing reaction in the form of a dermatitis. The development of these inflammatory skin .Jesions does not re-quire any internal predisposition or any internal condition. The character and the degree of the skin inflammation de-pends on the irritating agent. Therefore, the lesions may vary greatly with regard to the form, size, depth and duration. Dermatitis could be acute or chronic, erythematous, papular, vesicular, pustu-lar, moist, squamous, crusted or even gangrenous. According to the causative agent, the dermatitis could be classified: traumatic,caloric, irradiative, toxic or microgenic. Eczematous Dermatoses. Many stub-born skin diseases develop as a mani-festation of various internal disorders. These dermatoses are generally called eczermas. It is believed that eczema is a superficial skin inflammation which may be produced by various external irrita-tions, but it always involves a special in-ternal condition or an internal predispo-sition. Therefore, any kind of eczema is a dermatitis but not every dermatitis is an eczema. Because of this internal etiology, the eczematous skin lesions are, as a rule, symmetrically and bilaterally located and require for the treatment both systemic and topical treatment. Etiologically, eczemas may develop in the course of: 87 Squamous crusted eczema associated with hy-poestrogenism. 1. Deficient nutrition: vitamins, min-erals, fat, protein, trace elements etc. 2. Internal diseases: nephritis, hepatitis, enteritis, disorders of anal glands, prostate, uterus. 3. Hormonal disorders: gonadal hor-mones; estrogens, androgens, anterior pituitary hormones, thyroidal hor-mones, adrenal cortical hormones and 4. Intoxications; thallium, mercury, er-got, drugs etc. Allergic Dermatoses. Cutaneous al-lergy is a specifically acquired alteration in the capacity of living skin tissue to react. It results from exposure to an exciting agent or agents, and it appears upon re-exposure to the same or to an immunologically or chemically related agent. Allergic dermatoses in animals may be caused by foods, viruses, bacter-ia, fungi, internal or external parasites, chemicals, drugs, vitamins, hormones, antibiotics or various physical agents. Photosensitization is considered as a spe-cial type of a cutaneous allergy. Functional Diseases of the Skin. Func-tional derangements in the skin of ani-mals take a great variety of forms. In-cluded are disorders of sensation, dis-turbed functioning of sweat and sebace-ous glands, and deviations in hair and pigment development. 1. Pruritus. Generalized and localized itching. 2. Disorders in coil gland secretion. Ex-cessive sweating, generalized or lo-calized. Diminished or arrested sweat-ing. 3. Disorders in activity of sebaceous glands. Generalized or localized se-borrhea. Diminished or arrested ac-tivity of sebaceous glands. 4. Diseases of the hair follicles and the hair. Folliculitis. Alopecia; congeni-tal. acquired. Structural disorders of the hair: trichoptilosis, trichoorrhexis nodosa. 5. Disorders in pigmentation of skin and hair: hyperpigmentation, depigmenta-tion. Congenital Alopecia Hypertrophic Changes of the Skin. 1. Hypertrophy of the cutaneous cellu-lar tissue. 2. Hyperkeratosis. 3. Parakeratosis. Skin Tumors. Skin tumors can best be classified with regard to their location: epidermal, dermal, dermal appendages, subcutaneous tissue and as to their type: benign or malignant. 1. Epidermis: Benign; cutaneous horn, horny pads, papillomatosis. Malig-nant; squamous-cell carcinoma, basal cell carcinoma. 2. Dermis: Benign; fibroma, keloid, fib-romatosis of rabbits, lumpy skin dis-ease of cattle, neurofibroma, angioma, leiomyoma, sarcoid. Malignant; fibrosarcoma, neurogenic sarcoma, lymphosarcoma, mast cell sarcoma, malignant melanoma, infec-tious myxomatosis of rabbits. 3. Dermal appendages: hair follicle tu-mors, sweat gland tumors, sebaceous gland tumors. Iowa State College, Veterinarian 4. Subcutaneous tissue: lipoma. Skin Manifestations in the Course of Infectious Diseases. 1. Virus infections: pox, virus papular dermatitis in horses, contagious ec-thyma, infectious goat dermatitis, foot and mouth disease, vesicular stomatitis, vesicular exanthema of swine, coital vesicular exanthema in horses, rinderpest, cutaneous strang-les, hog cholera, distemper complex, pemphigus, scrapie. 2. Bacterial infections : impetigo, pyo-genic dermatitis, contagious derma-titis in horses, swine erysipelas, an-thrax, malignant edema, tuberculosis, glanders, ulcerous lymphagitis in horses and dogs (Nocardiosis). Pyogenic dermatitis Skin Disorders Caused by Fungi. Der-matoses of fungal origin may be classi-fied as follows: 1. Blastomycoses: equine blastomycosis, canine blastomycosis. 2. Dermatomycoses: ringworm-tinea. Microsporum group: Microsporum canis, M. gypseum, M. audouini. Trichophyton group: Trichophyton equinum, T. mentagrophytes, T . ver-rucosum, T. schoenleini, T. gallinae. 3. Cutaneous moniliasis: Monilia albi-cans. Issue 2, 1958-59 4. Mycetomycoses. actinomycosis, ac-tinobacillosis, farcy of cattle, strepto-thricosis in dogs, botryomycosis. 5. Sporotrichosis. Skin Manifestations of Protozoal Ori-gin. 1. Babesiosis. 2. Surra. 3. Mal de Caderas. 4. Dourine. 5. Leshmaniosis. 6. Spiro-chaetosis. Dermatoses Associated with Hel-minthes. 1. Nematodiases: rhabditidiasis, ancy-lostomiasis, bunostomiasis, parafilar-iasis, stephanofilariasis, habronemia-sis, dirofilariasis, dracunculiasis, on-chocerciasis. 2. Trematodiasis. Acarine Dermatoses Associated with Ticks and Mites. 1. Ixodes acariasis. 2. Dermanysus acar-iasis. 3. Trombiculidiasis. 4. Sarcoptic acariasis: Genus sarcoptes, genus cnemi-docoptes, genus notoedres, genus psorop-tes, genus chorioptes, genus otodectes. 5. Demodectic acariasis. Dermatoses Caused by Insects. 1. Pediculosis. 2. Siphonaptera. 3. Dip-tera. 4. Hemiptera. 5. Coleoptera. 6. Hy-menoptera. 7. Lepidoptera. .F:".a Pustular and phlegmonous form of Demodectic mange. (Continued from page 85) squirrel during hibernation. Master of Sci-ence Thesis. Iowa State College Library, Ames. 1927. 10. Rasmussen, A. T. Theories of hibernation. Amer. Nat. 50:609-662. 1916. 11. Sheldon, E. F . The so-called hibernating gland in mammals : a form of adipose tis-sue. Anat. Rec. 28:331-343. 1924. 12. Simpson, S. The food factor in hibernation. Proc. Soc. Exp. BioI. Med. 9:92-93. 1912. 89 

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Etiology and Classification of Animal Dermatoses

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