Six adult dogs were presented with an unusual bullous dermatosis aecting the glabrous skin of the ventral abdomen and medial thighs. Clinically,¯accid bullae were accompanied by erythema, ulceration, haemorrhage and hyperpigmentation in four of six dogs; the remaining two dogs had thin skin without grossly apparent bullae. Histologically, subepidermal bullae and clefting, vascular proliferation and dilatation (phlebectasia), and alteration in the density and staining of super®cial dermal collagen were seen in all dogs. In all cases, corticosteroid-containing topical products had been applied to the aected areas prior to the development of the dermatosis; skin lesions resolved when topical corticosteroids were withdrawn. Follow-up biopsy of three dogs showed resolution of the previously abnormal collagen and subepidermal clefting. Residual lesions included phlebectasia, comedones and hyperpigmentation. The authors postulate that subepidermal clefting was due to local, corticosteroid-induced skin fragility. This is the ®rst report, to our knowledge, of bullous skin disease in dogs resulting from topical corticosteroid therapy.

Résumé— Une revue de la physiopathologie et de Thistopathologie des dermites de contact par allergie et irritation est présentée. Le rôle des lymphocytes, des cellules de Langerhans, des basophiles et des éosinophiles est discuté. Des résultates précédents non‐publiés de dermites de contact expérimentales chez le chien sont présentées. Les résumés des cas cliniques de dermites de contact spontannées chez le chien et le chat présentées lors du 9e congrès de l'AAVD sont inclus. Les cas cliniques sont comparés aux cas expérimentaux et aux aspects histopathologiques décrits chez 1'homme. Des lésions avec un infiltrat riche en éosinophiles ont été retrouvées dans trois cas; une discussion sur la possibilité d'existence d'IgE à la surface des cellules de Langerhans entrainant à la fois une réponse de type I et de type IV chez ces patients est développée. [Walder, E. J., Conroy, J. D. Contact dermatitis in dogs and cats: pathogenesis, histopathology, experimental induction and case reports (Dermite de contact chez le chien et le chat: pathogénie, histopathologie, induction expérimentale et cas cliniques). Resumen— Se revisa la fisiopatología e histopatología de la dermatitis por contacto alérgica y por irritación en la especie humana y en los animales. Se discute el papel de los linfocitos, las células de Langerhans, los basófilos y los eosinófilos. Se presentan datos sobre la dermatitis por contacto alérgica y por irritación en el perro no descritos hasta la fecha. Se incluyen los resumenes de los casos clinicos presentados en las das jornadas de la Academia Americana de Dermatología Veterinaria. Se comparan los casos clinicos con los hallazgos expérimentales en el perro y con las caracteristícas histopatológicas recientemente descritas en la especie humana. En tres casos se descubrieron vesiculo‐pústulas con abundantes eosinófilos; se especula con la posibilidad de que células de Langerhens cargadas con IgE induzcan reacciones mixtas de hipersensibilidad de tipo I y IV (“atopia por contacto”). [Walder, E. J., Conroy, J. D. Contact dermatitis in dogs and cats: pathogenesis, histopathology, experimental induction and case reports (Dermatitis por contacto en el perro y en el gato: patogénesis, histopatología, reproducción experimental y casos clínicos). Zusammenfassung— Es erfolgt eine übersicht über Pathophysiologie und Histopothologie der irritativen und allergischen Kontakdermatitis das Mensch und Tier. Es werden die Rollen der Lymphozyton, Langerhans Zellen, basne und eosinophilen Granulozyten diskutiert. Es werden unveröffentlichte Daten über experimentelle irritative und allergische Kontaktdermatitis bei Hunden vorgestellt. Die Zusammenfassungen von Fallstudien spontaner Kontaktdermatitis bei Hund und Katze, veröffentlicht beim 9. Jahrestreffen der American Academy of Veterinary Dermatology werden miteingeschlossen. Die Fallstudien werden mit den experimentellen Ergebnissen beim Hund und mit den klassischen und kürzlich beschriebenen histopatholo‐gischen Bildern beim Menschen verglichen. In drei Fällen wurden vesik...

Four domestic rabbits were presented with a history of nonpruritic scale. Multiple skin biopsies revealed findings compatible with sebaceous adenitis as reported in other species: inflammation directed at the sebaceous gland, and/or an absence of sebaceous glands, a perifollicular lymphocytic infiltrate at the level of the absent sebaceous glands, hyperkeratosis, follicular keratosis, follicular dystrophy, perifollicular fibrosis, and a mural infiltrative lymphocytic folliculitis. Histological changes not consistent with sebaceous adenitis in other species were interface dermatitis and interface folliculitis with single cell necrosis and basal cell hydropic degeneration.

No abstract

Angiomatosis, a heterogeneous group of potentially progressive, non‐neoplastic, possibly congenital vascular proliferations, has not been well documented in dogs and cats. The pathogenesis of angiomatosis is largely unknown. The lesions can be categorized as progressive angiomatosis (PA), scrotal‐type vascular hamartoma (STVH), or angiomatosis secondary to lymphedema (ASL). Spontaneous regression has not been seen. Irregular, red to blue macules, patches, nodules and plaques may partially blanch with diascopy. Periodic hemorrhaging may occur. Progressive angiomatosis may develop at any age and most often affects the extremities, but may occur elsewhere. Breed or sex predilections are not known. Canine STVH affects middle‐aged or older dogs and develops on the scrotum, tail or caudal trunk. Breeds with pigmented scrotal skin are predisposed. Angiomatosis secondary to lymphedema is a rare condition affecting extremities. Progressive angiomatosis is characterized by interconnected foci of dermal and subcutaneous blood‐filled vascular structures of variable size, separated by normal or myxomatous mesenchymal tissue. The vascular channels may have large lumens or resemble capillaries and are lined by mature or slightly enlarged endothelial cells. Thrombosis and intraluminal papillary endothelial hyperplasia may be present. Variable amounts of smooth muscle and fibrous tissue indicate the presence of arterioles and veins. With STVH, clusters are composed of central larger vessels surrounded by capillary buds. With ASL, there is marked lymphedema, primary hypoplasia of the deep lymphatics, and prominent secondary vascular proliferation. Most forms of canine and feline angiomatoses are newly recognized syndromes; as more cases are gathered and documented, nomenclature and classification may change. Funding: Self‐funded.