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Research article2020Peer reviewedOpen access

Topical treatment of equine sarcoids with imiquimod 5% cream or Sanguinaria canadensis and zinc chloride - an open prospective study

Pettersson, Carina M.; Brostrom, Hans; Humblot, Patrice; Bergvall, Kerstin E.


Background Equine sarcoids are the most prevalent skin neoplasm in horses worldwide. Although several treatments are available, none are consistently effective and recurrence is common. Objectives To evaluate the efficacy and safety of topical imiquimod 5% cream andSanguinaria canadensis + zinc chloride for treatment of equine sarcoids and investigate possible systemic effects on distant untreated sarcoids. Animals/Tumours Twenty-five client-owned horses with a total of 164 tumours were included in the study. Fifty-seven tumours were treated and 107 tumours were left untreated. Methods and materials Biopsies were taken from a minimum of one tumour per horse and the rest were diagnosed based on clinical appearance as likely sarcoids. Imiquimod 5% (A) was applied three times weekly, whileSanguinaria canadensis + zinc chloride (X) was applied every fourth day after a six day daily initiation phase. Treatment continued until clinical remission or for a maximum of 45 weeks, with a long follow-up period (mean 34 months). Biopsies of sarcoids were re-taken before treatment termination and at follow-up if the owner gave consent. Results Complete remission was recorded in 84.4% (A) and 75.0% (X) of the tumours. Relapse was recorded in 7.3% (A) and 21.4% (X). Spontaneous remission was observed in 1.9% of untreated tumours. No systemic effect on untreated tumours was detected. During treatment varying degrees of local inflammatory reaction were common. Conclusions and clinical relevance Both treatments were considered effective and safe. Smaller tumours responded more favourably to treatment. Relapse rate was low and not observed in sarcoids with repeat biopsies before treatment termination.

Published in

Veterinary Dermatology
2020, Volume: 31, number: 6, pages: 471-481
Publisher: WILEY