A prospective study of the clinical findings, treatment and histopathology of 44 cases of pyotraumatic dermatitis

Abstract

Pyotraumatic dermatitis (hot spot) is a common clinical syndrome in dogs but there are few prospective scientific studies related to it. The aim of this study was to investigate correlations among clinical pyotraumatic dermatitis, histopathology of the lesions and possible predisposing causes. The relationship of these with breed, age, sex and location of lesion was assessed statistically. A clinical diagnosis of acute pyotraumatic dermatitis was made in 44 privately owned dogs. Males exceeded females (P = 0.0348) and lesions were more common in dogs aged 4 years or less (P < 0.0001). Lesions were most often seen on the cheek, neck and lateral thigh with a significant correlation between breed and site of lesion (P < 0.0001). In 31 cases a possible underlying cause was found or suspected. In contrast to previous studies, no otitis externa was recorded and the study was conducted in an area without endemic fleas. Fourteen breeds were represented of which Rottweiler, German shepherd dog and golden retriever were most common. There was no significant seasonal incidence and no correlation among site of lesion and cause, time of year, age or sex. Histopathologically, the dogs could be separated into four patterns by the presence or absence of eosinophils and/or folliculitis. Eosinophils have not previously been recorded in pyotraumatic dermatitis but were seen in 29 cases. Acute folliculitis was seen in 20 cases. However, no correlation was seen among age, sex, breed, underlying cause or site of lesion and histopathology. Twenty-seven cases were cultured for bacteria of which 25 grew Staphylococcus intermedius and two were negative.

Hot Spots beim Hund

“…Rassen mit langem, schweren Fell und/oder dichter Unterwolle sind prädisponiert, wie zum Beispiel Golden und Labrador Retriever, Deutscher Schäferhund, Neufundländer, Berner Sennenhund, Leonberger, Collie und Bernhardiner. In einer schwedischen Studie von 2004 mit 44 Hunden zeigte allerdings der Rottweiler das höchste Risiko, Hot Spots zu bekommen [2]. Weiterhin fiel auf, dass es eine Korrelation zwischen Rasse und Lokalisation der Läsion gab: Alle 10 Rottweiler hatten Hot Spots an der Wange oder im Nacken, und bei allen 8 Deutschen Schäferhunden war der laterale Oberschenkel oder die Hüfte betroffen.…”

“…Dies könnte damit zusammenhängen, dass das Fell an diesen Stellen bei der jeweiligen Rasse besonders dicht ist. Insgesamt traten bei allen untersuchten Hunden die meisten Hot Spots an der Wange auf (50 % der Fälle), gefolgt vom lateralen Oberschenkel, Nacken und Lumbalbereich [2].…”

“…In der gleichen Studie wurde auch herausgefunden, dass es bei den betroffenen Hunden keine Saisonalität bezüglich des Auftretens von Hot Spots gab. 25 der 41 Hunde entwickelten Hot Spots zwischen April und September, 19 Hunde zwischen Oktober und März [2].…”

“…Hot Spots können solitär oder multipel auftreten und variieren in der Größe von 3-20 cm [2]. Der typische Hot Spot ist eine gut abgegrenzte, rundliche Läsion mit Erythem und purulentem Exsudat, welches die Haare verklebt.…”

Efficacy of Imidacloprid 10% and Imidacloprid 10% plus Moxidectin 2.5% against Natural Lice (Trichodectes canis) Infestations in Dogs

“…In addition to the distress caused by the lice themselves, T. canis can also act as effective intermediate hosts for the tapeworm Dipylidium caninum (Jueco 1982, Wall andShearer 1997). Pruritus caused by lice can cause self-trauma as demonstrated by a study conducted in Sweden where sucking lice (Linognathus setosus) appeared to be the underlying cause of 23 % of cases of pyotraumatic dermatitis (hot spot) in a study of 44 dogs (Holm et al 2004). Traditional treatments tended to be ineffective against stages within the egg, so two treatments were often necessary (O'Dair 1992, Scott et al 1995.…”