Management of diabetes mellitus (DM) may be complicated in dogs with concurrent disorders due to an increase in concentrations of counter-regulatory hormones, such as glucagon, catecholamines, corticosteroids, or growth hormone.

In a study of 221 diabetic dogs, the mean age at time of diagnosis was 8.9 ± 2.9 years, and the sex demographic was 89 spayed females, 78 neutered males, 38 intact males and 16 intact females. Purebred dogs accounted for 163 of the 221 cases (74%), and the most frequently affected breeds were miniature schnauzers (27 cases), Labrador retrievers (18), and miniature poodles (16); 58 dogs (26%) were mixed breeds. A second recent study involved 45 dogs with DM evaluated for concurrent skin disease.

The most common concurrent diseases were:

• Diabetic ketoacidosis (ketonuria and metabolic acidosis) was diagnosed in 15% of dogs.
• Urinary tract infection was present in 21% of 159 cultured urine samples, and the most common bacterium isolated was E. coli.
• Cushing's syndrome was diagnosed in 51 (23%) of cases. Diagnosis was established by history, clinical signs, and results of adrenal function tests in 50 dogs and necropsy in one dog. Low-dose dexamethasone suppression (LDDS) test results were abnormal in 41 of the 50 dogs tested. Five dogs had ACTH stimulation tests consistent with Cushing's syndrome, and four of them also had abnormal LDDS tests. Another 47 dogs tested had normal adrenal function tests.
• Hypothyroidism was diagnosed in 8 (4%) of the dogs based on clinical signs and TSH stimulation tests (5 dogs), low T4 and high cTSH (2 dogs) and necropsy (1 dog).
• Acute pancreatitis was present in 28 (13%) of cases based on clinical signs, abdominal ultrasound or histologic findings. In addition, more than half of the dogs had high amylase and lipase concentrations.
• Dermatologic disorders most commonly seen in the 45 diabetic dogs studied included: bacterial dermatitis (84%), otitis (58%), allergic dermatitis (49%), malassezia-induced dermatitis (42%), and endocrinopathies (~40%). Also seen with DM are: demodecosis, often generalized in dogs; cutaneous lymphoma especially in cats, but also in dogs; and necrolytic migratory erythema (aka hepatocutaneous syndrome). Allergic pruritic skin disease was present in 22 of the 45 dogs (49%) and preceded the DM by at least 2 years.