A Retrospective Evaluation of Equine Cutaneous Lesions Diagnosed in Southern Brazil

Matheus Viezzer Bianchi, Gisele Silva Boos, Lauren Santos de Mello, Thainã Piccolo Vargas, Luciana Sonne, David Driemeier, Saulo Petinatti Pavarini


Background: Cutaneous lesions in horses are common, accounting for approximately 50% of all neoplasms of this species, and can cause irritability, pruritus and predispose to secondary infections. Studies have provided information of frequency of cutaneous neoplasms in horses, but few included non-neoplastic lesions. The aim of this study is to identify the frequency of cutaneous lesions in horses diagnosed in Southern Brazil, through a retrospective study and identification of the anatomic location of the lesion, the breed, gender and age of the animals affected.

Materials, Methods & Results: A retrospective study on skin lesions in horses using the database of the Veterinary Pathology Laboratory located in Southern Brazil was carried out from January 2000 to February 2013. Cases were searched for and selected by diagnosis, considering age, breed, gender, location and time of occurrence. The most common lesions included sarcoid, exuberant granulation tissue, squamous cell carcinoma (SCC), pythiosis, habronemiasis, melanoma, papillomatosis and Culicoides hypersensitivity. The most affected age range for sarcoid was animals from 1 to 5 years of age and for SCC was over 15 years of age. There was a positive association between sarcoid occurrence and being female and between SCC and habronemiasis and being male. Sarcoid, exuberant granulation tissue, pythiosis and habronemiasis most frequently involved the limbs, while SCC affected the urogenital and ocular systems and melanoma affected the tail. Pythiosis, habronemiasis, Culicoides hypersensitivity and nodular collagenolytic granuloma had seasonal occurrences. Sarcoid, exuberant granulation tissue and SCC were the most commonly diagnosed lesions. Sarcoid affected mostly younger animals, while SCC commonly affected older animals. Habronemiasis and Culicoides hypersensitivity occurred mostly during the spring and summer, while pythiosis most often presented during autumn and winter.

Discussion: The frequency of neoplastic lesions in the present work was similar to other studies. Among horse skin neoplasms, sarcoid is the most common, as was observed in this study. Sarcoid primarily affects young animals and most of these have an age range between one and five years, which was also noted and supported by statistical analysis. EGT is the most common non-neoplastic lesion in the skin of horses, most commonly in the limbs. The high frequency described may be related to a higher genetic predisposition or due to the employment of these horses in intensive work. SCC is the second most common skin neoplasm and often affects older horses, as it was observed. Urogenital tract and males were the most affected location and gender. Due to their ventral location, smegma may be a more likely etiology. It was observed a lower frequency of pythiosis and this may be due to the geographical location of the laboratory, where economy it is not based on livestock or rice farming, which can predispose animals to stay in stagnant water. Cutaneous habronemiasis is often diagnosed during warm months that have high biting insect activity, as observed here, where 75% of the cases occurred during the spring-summer. Differential diagnoses of nodular collagenolytic granuloma and habronemiasis was based not only on the presence of the parasite but also on the morphologic features of the lesion. Culicoides hypersensitivity is the most common and severe allergic condition in horses distributed worldwide because of the favorable weather conditions for the reproduction of the insect. In this study, 75% of the cases occurred during the spring-summer. Lesions are usually multiple, as it was observed in 50% of the cases.


horses diseases; cutaneous lesions; neoplasm; tumour-like lesions; inflammatory lesions.

Full Text:



Baker J.R. & Leyland A. 1975. Histological survey of the tumours of the horse, with particular reference to those of the skin. Veterinary Record. 96(19): 419-422.

Brum J.S., Souza T.M. & Barros C.S.L. 2010. Aspectos epidemiológicos e distribuição anatômica das diferentes formas clínicas do sarcoide equino no Rio Grande do Sul: 40 casos. Pesquisa Veterinária Brasileira. 30(10): 839-843.

Celeste C.J., Deschene K., Riley C.B. & Theoret C.L. 2011. Regional differences in wound oxygenation during normal healing in an equine model of cutaneous fibroproliferative disorder. Wound Repair and Regeneration. 19(1): 89-97.

Kerr K.M & Alden C.L. 1974. Equine neoplasia - a ten year survey. Proceedings of American Association of Veterinary Laboratory Diagnosticians. 17: 183-187.

Marcolongo-Pereira C., Sallis E.S.V. & Raffi M.B. 2012. Epidemiologia da pitiose equina na Região Sul do Rio Grande do Sul. Pesquisa Veterinária Brasileira. 32(9): 865-868.

Marti E., Lazary S., Antczak D.F. & Gerber H. 1993. Report of the first international workshop on equine sarcoid. Equine Veterinary Journal. 25(5): 397-407.

Pascoe R.R. & Summers P.M. 1981. Clinical survey of tumours and tumour-like lesions in horses in south east Queensland. Equine Veterinary Journal. 13(4): 235-239.

Pusterla N., Watson J.L., Wilson W.D., Affolter V.K. & Spier S.J. 2003. Cutaneous and ocular habronemiasis in horses: 63 cases (1988-2002). Journal of the American Veterinary Medical Association. 222(7): 978-982.

Ramos A.T., Souza A.B., Norte D.M., Ferreira J.L.M & Fernandes C.G. 2008. Tumores em animais de produção: aspectos comparativos. Ciência Rural. 38(1): 148-154.

Sallis E.S.V., Pereira D.I.B. & Raffi M.B. 2003. Pitiose cutânea em equinos: 14 casos. Ciência Rural. 33(5): 899-903.

Scott D.W. 2007. Color atlas of farm animal dermatology. Ames: Blackwell, 252p.

Scott D.W. & Miller W.H. 2003. Equine Dermatology. Philadelphia: Saunders, 823p.

Souza T.M., Brum J.S., Fighera R.A., Brass K.E. & Barros C.S.L. 2011. Prevalência de tumores cutâneos de equinos diagnosticados no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria, Rio Grande do Sul. Pesquisa Veterinária Brasileira. 31(5): 379-382.

Sundberg J.P., Burnstein T., Page E.H., Kirkham W.W. & Robinson F.R. 1977. Neoplasms of Equidae. Journal of the American Veterinary Medical Association. 170(2): 150-152.

Valentine B.A. 2005. Equine cutaneous non-neoplastic nodular and proliferative lesions in the Pacific Northwest. Veterinary Dermatology. 16(6): 425-428.

Valentine B.A. 2006. Survey of equine cutaneous neoplasia in the Pacific Northwest. Journal of Veterinary Diagnostic Investigation. 18(1): 123-126.

Van Den Top J.G.B., Emsink J.M., Gröne A., Klein W.R., Barnevald A. & Van Weeren P.R. 2010. Penile and preputial tumours in the horse: literature review and proposal of a standardized approach. Equine Veterinary Journal. 42(8): 746-757.

Wobeser B.K., Davies J.L., Hill J.E., Jackson M.L., Kidney B.A., Townsend H.G.G & Allen A.L. 2010. Epidemiology of equine sarcoids in horses in western Canada. Canadian Veterinary Journal. 51(10): 1103-1108.

DOI: https://doi.org/10.22456/1679-9216.81154

Copyright (c) 2018 Matheus Viezzer Bianchi, Gisele Silva Boos, Lauren Santos de Mello, Thainã Piccolo Vargas, Luciana Sonne, David Driemeier, Saulo Petinatti Pavarini

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.