Allergic contact dermatitis in the dog. Principles and diagnosis

Allergic contact dermatitis is a rare hypersensitivity disorder in the dog. Clinical diagnosis is not easy. Primary lesions are transient. Secondary lesions caused by chronic inflammation and self-trauma are commonly present on typical areas, especially in sparsely haired regions and on the feet. A presumptive diagnosis can be made based on the history, clinical signs, and positive standardized closed patch testing. Histopathology and basophil degranulation testing may also be helpful in supporting the diagnosis and in identifying the offending allergens. However, a definitive diagnosis can be made only after restriction-provocation testing. With better understanding of the pathogenesis and clinical signs, and with increased availability of diagnostic tests (especially a standardized closed patch test), increased recognition of this dermatosis is expected.     

Respiratory failure attributable to moxidectin intoxication in a dog

A 5-month-old 22-kg (48.4-lb) sexually intact male Collie was examined after ingesting a moxidectin-containing deworming medication. The dog was comatose and had respiratory arrest after progressively worsening lethargy, ataxia, and seizures. Exposure was confirmed by isolation of moxidectin from a biopsy specimen of adipose tissue, using liquid chromatography-mass spectroscopy methods. Treatment included use of intermittent positive-pressure ventilation, activated charcoal and cathartic administered enterally, nutrients administered via nasogastric tube, and intensive supportive care. The dog was weaned from a ventilator on day 6 after ingestion and was discharged on day 10. The dog was considered clinically normal during examination 24 days after ingestion. On the basis of the dog reported here and toxicologic data provided by the manufacturer of the deworming product, some Collies may have increased susceptibility to products containing high doses of moxidectin.     

Metastatic calcification in a dog attributable to ingestion of a tacalcitol ointment

A 22-week-old 21-kg female Bernese Mountain Dog ingested a topical antipsoriatic preparation containing the synthetic vitamin D analog tacalcitol. The dog died after a history of lethargy, recumbency, paresis of the hindlimbs, increased rectal temperature, dyspnea, and hematemesis. Histologic examination revealed metastatic calcification in the kidneys, lungs, myocardium, brain, stomach, and tear glands. The appearance of soft tissue mineralization in multiple organs is consistent with hypercalcemia derived from excessive vitamin D uptake. Oral toxicity studies for tacalcitol in the dog are not available, but the present report emphasizes the extraordinary toxic risk of drugs containing this vitamin D analog to dogs.     

Recurring tetraparesis attributable to a heartworm in the epidural space of a dog

Recurring nonambulatory tetraparesis caused by a heartworm in the epidural space was diagnosed in a dog. On myelography and digital subtraction imaging, the parasite appeared as a large extradural mass. Surgical removal of a mature, female Dirofilaria immitis resulted in resolution of the neurologic signs.     

Acute oral marijuana poisoning in the dog

Ingestion of marijuana by three dogs in unrelated incidents resulted in depression-type toxicosis in each case. The most evident clinical signs were central nervous system depression and ataxia. Emesis and hypothermia were noted in two of the cases. Symptomatic and supportive treatment was accompanied by clinical improvement. In two cases, recovery was slow, with clinical signs apparent for 36 to 48 hours after onset. In the third case, clinical signs were apparent for only 3 hours.     

Hookworm dermatitis due to Uncinaria stenocephala in a dog from Saskatchewan

Uncinaria stenocephala hookworm dermatitis (uncinariosis) was diagnosed on fecal examination and macerated skin biopsy in a 1.5-year-old greyhound dog from Saskatchewan. This is the first reported case in Canada. Treatment with moxidectin cleared gastrointestinal and dermal infections.     

Macrohematuria and life-threatening anemia attributable to subepithelial vascular ectasia of the urinary bladder in a dog

Hematuria leading to life-threatening anemia was evaluated in a 9-year-old male dog. At surgery, an abnormal vessel resembling an ulcerated varicose vein was found on the surface of the bladder mucosa. After removal of the lesion, hematuria ceased and had not recurred 22 months later.     

Superficial necrolytic dermatitis and a pancreatic endocrine tumour in a dog

A 13-year-old dog was referred for a severe dermatological problem of 12 months duration. Skin biopsy results were compatible with superficial necrolytic dermatitis. The only laboratory abnormalities were hyperglycaemia and hyperglucagonaemia. These findings suggested a pancreatic endocrine tumour in association with superficial necrolytic dermatitis. Abdominal ultrasound examination was unremarkable. The dog was euthanased due to the lack of clinical improvement following symptomatic therapy. Postmortem examination revealed a pancreatic endocrine tumour with liver metastases. Pancreatic endocrine tumour cells were immunoreactive for glucagon, insulin and islet amyloid polypeptide.     

Basal cell carcinoma in a dog with chronic solar dermatitis

A seven‐year‐old, entire male, American Staffordshire bull terrier was diagnosed with chronic solar dermatitis and basal cell carcinoma, based on physical examination, cutaneous cytology and histopathology. Immunohistochemistry revealed that the tumour cells did not express p53. To the authors’ knowledge this is the first reported case of canine basal cell carcinoma developing as a complication of chronic solar dermatitis.     

A review of lameness attributable to the shoulder in the dog: part two

The scapulohumeral joint is a common site of forelimb lameness in the dog. Establishing a definitive diagnosis may be difficult because of the limitations of orthopedic examination and radiographs and the inherent elusiveness of the associated conditions. The intent of this review is to present, in a single reference, the pathophysiology, diagnosis, and treatment of reported causes of lameness intrinsically associated with the shoulder. Part One of this series discusses conditions associated with cartilage and bone maturation disorders and joint instability, while Part Two reviews tendon diseases, muscle disorders, synovial diseases, and soft-tissue mineralization disorders.     

Superficial necrolytic dermatitis associated with extrapancreatic glucagonoma in a dog

An 11-year-old Shih Tzu presented with crusting and erythema, mainly on the abdomen and the root of the tail. Based on histopathological findings, blood examinations and necropsy findings, the condition was diagnosed as superficial necrolytic dermatitis associated with a glucagon-secreting extrapancreatic neuroendocrine tumour. Gross necropsy revealed tumour invasion into the spleen, liver, adrenal glands and mesenteric lymph nodes. Immunohistochemical analysis of the neoplastic cells revealed that the tumour was a glucagonoma, consistent with earlier findings of persistent glucagonaemia and hypoaminoacidaemia.     

A review of lameness attributable to the shoulder in the dog: part one

The scapulohumeral joint is a common site of forelimb lameness in the dog. Establishing a definitive diagnosis may be difficult because of the limitations of orthopedic examination and radiographs and the inherent elusiveness of the associated conditions. The intent of this review is to present, in a single reference, the pathophysiology, diagnosis, and treatment of reported causes of lameness intrinsically associated with the shoulder. Part One of this series discusses conditions associated with cartilage and bone maturation disorders and joint instability, while Part Two reviews tendon diseases, muscle disorders, synovial diseases, and soft-tissue mineralization disorders.