The mite Demodex injai causes demodicosis, an uncommon, chronic, and recurrent parasitic dermatopathy in dogs. Demodicosis is characterized by an excessive proliferation of the Demodex injai mite in the pilosebaceous unit. Typically, demodicosis occurs in adults, and is associated with an underlying disease or a specific host immunodeficiency. Here, we describe the epidemiological, clinical, dermatological, and therapeutic aspects of Demodex injai demodicosis in dogs (n=8) at the Hospital Unit for Companion Animals of the Pontifical Catholic University of Paraná in Brazil. The affected dogs were predominantly purebred, had a mean age of eight years, and showed no gender predisposition. The lesions were predominantly alopecic and erythematous-desquamatory, associated with follicular dyskeratosis and greasiness of the coat, and mainly affected the facial region, in addition to the back and limbs. The animals had a history of allergic, dyskeratotic, endocrine, neoplastic, and immunosuppressive comorbidities. The diagnosis of demodicosis was based on multiple skin scrapings, trichogram, and acetate tape impression of the lesion areas, macroscopic observation, and morphological characterization of the mite. Macrocyclic lactones were effectively used for treatment in most cases; however, improvement of the condition may be related to adjunctive treatment of the underlying disease. Key words: Canine. Clinical signs. Demodectic mange. Dermatopathy. Mites. ResumoDemodiciose provocada pelo ácaro Demodex injai é uma dermatopatia parasitária, crônica, recorrente, incomum em cães, caracterizada pela proliferação excessiva do ácaro na unidade pilossebácea. É frequentemente caracterizada como de surto adulto, generalizada e associada a uma doença de base ou a uma imunodeficiência específica inerente ao hospedeiro. O presente relato tem como objetivo descrever os aspectos epidemiológicos, clínico-dermatológicos e o tratamento da demodiciose por Demodex injai em cães (n=8) atendidos na Unidade Hospitalar para Animais de Companhia da Pontifícia Universidade Católica do Paraná, em São José dos Pinhais, Paraná, Brasil. Os animais acometidos apresentaram idade média de oito anos, predominantemente de raças puras e não houve predisposição sexual. As lesões tinham características predominantemente alopécicas e eritêmato-descamativas, associadas à disqueratose folicular e untuosidade da pelagem, acometendo principalmente a região da face, mas também o dorso e os membros. Os animais apresentavam histórico de comorbidades alérgicas, disqueratóticas, endócrinas, neoplásicas ou imunossupressivas de base. O diagnóstico da demodiciose foi estabelecido por múltiplos raspados de pele, tricograma e técnica de beliscamento por fita adesiva em áreas lesionais, seguindo à observação macroscópica e caracterização morfológica do ácaro. Instituiu-se tratamento com lactonas macrocíclicas, que se mostraram eficazes na maioria dos casos, entretanto, a involução do quadro pode estar relacionado ao tratamento adjunto das doenças de base.

Background: Idiopathic diffuse lipomatosis is a rare disease in veterinary medicine. It is characterized by excessive proliferation of adipocytes, which results in the formation of fatty tumours throughout the body. In humans, this disease is also known as Madelung’s disease or multiple symmetric lipomatosis and is classifed as type I and II. The aim of this study was to investigate two cases of dogs diagnosed with idiopathic diffuse lipomatosis and compare their characteristics with those found in humans.Cases: Case 1 - A 3-year-old standard poodle female was taken for veterinary evaluation for a slow-growing tumoural lesion over the neck and trunk. The tumours measured >30 cm in diameter that caused irregular and protruding folds resulting in a signifcant loss of body architecture. No clinical signs of adjacent systemic disease were observed. Elliptical excisions of the skin revealed diffuse mature adipocytes and hyperplastic and dysplastic lipoblast hypertrophy of the panniculus, which was associated with epidermodermal hypotrophy and skin appendages. The combination of these fndings supported a diagnosis of idiopathic diffuse lipomatosis. The animal underwent surgical therapy. However, the clinical symptoms recurred within two months. Owing to the continuous recurrence of tumours and history of three other surgeries, it was decided to euthanize the animal. Case 2 - An 11-year-old female cocker spaniel preenting tumoural lesions of insidious evolution and widespread distribution. Clinical examination revealed the presence of multiple subcutaneous tumours in the lateral, lumbosacral, and abdominal regions of the pelvic limb. No clinical signs of adjacent systemic disease were observed. Biopsies of tumoural lesions also supported the diagnosis of idiopathic diffuse lipomatosis. The animal was fed a low-calorie diet, after which its body weight decreased without inducing any changes in tumour size. In addition, the animal underwent surgical treatment for removal of the largest tumours. After surgery, the animal was monitored for 1year and showed no tumour recurrence.Discussion: In veterinary medicine, lipomatosis is an extremely rare disease. Therefore, before diagnosing a case, it is necessary to exclude other proliferative disorders of the adipose tissue, among which, the most common are lipomas and liposarcomas. There are no genetic studies related to lipolytic activity or adipocyte proliferation in animals. However, it is believed that the aetiology of idiopathic diffuse lipomatosis is similar to the pathophysiology of the human form of multiple symmetrical lipomatosis, and could be associated with a primary lipid metabolism disorder. In this study, the two cases described showed a distinct distribution in the type of tumours. In case 1, the tumours were well defned and focused in the cervical and thoracic region, a pattern similar to human type I lipomatosis. However, in case 2, the fat accumulationswere diffuse and mainly located in the posterior region of the animal’s body similar to type II lipomatosis. No animals presented intra-abdominal or intrathoracic fat infltration, diagnosed by ultrasound or radiography. There is no description of any treatment capable of being effective. However, surgical procedures are recommended to minimize the occurrence of tumours and improve the quality of life of the affected animals. In the two cases described in this study, it was diffcult to completely resect the tumours. In the frst case, the recurrence of fatty deposits and performance of multiple interventions resulted in a poor quality of life of the animal, which was fnally euthanized to avoid further suffering. Therefore, frequentrecurrences might correlate with a poor prognosis in dogs.Keywords: fat, subcutaneous, tumour, skin.