For the larger study (221 cases), the mean duration of clinical signs was 1.3 ± 1.9 months. Polydipsia and polyuria were present in 82%, lethargy (57%), inappetence (45%), vomiting (40%), weight loss (39%), polyphagia (22%), and diarrhea (13%). Most dogs (48%) were overweight, although 19% were underweight. Most dogs (50%) were well hydrated, but 32% were moderately dehydrated and 18% were severely dehydrated. Other findings included hepatomegaly (61%), cataracts (26%) and cardiac murmurs (26%).

In the dermatologic study, 21 of the 45 dogs (47%) had received corticosteroid therapy recently. Nine of them had received anti-inflammatory doses of corticosteroids intermittently for a year or more, and 5 dogs had been given immunosuppressive doses of corticosteroids less than a month before the diagnosis of DM. Of those with allergic skin disease (22 dogs), 3 had food allergies, 1 had flea allergic dermatitis, and 18 had atopic dermatitis.

Bacterial skin infection was present in 38 dogs, of which 28 had only superficial infections, 6 had both superficial and deep pyoderma, and 4 had only deep infections most commonly in the form of interdigital nodules. Most of the dogs exhibited pruritis. Of the 26 dogs with otitis which presented after the onset of DM, cytology revealed yeast, bacteria, or a mixture of both.

Dermatitis from malassezia was detected in 19 dogs, and 13 of these had a prior diagnosis of allergic dermatitis. Of the 6 remaining dogs with malassezia, 4 had necrolytic migratory erythema (also called hepatocutaneous syndrome, metabolic epidermal necrosis, or superficial necrolytic dermatitis). One other dog in this 45 case study had necrolytic migratory erythema and it was not associated with yeast infection. The most common sites for yeast overgrowth were interdigital spaces (10 dogs) and claw fold (8 dogs).

Hyperadrenocorticism was present in 13 of 45 (29%) dogs with DM and skin disease. Hypothyroidism was diagnosed in 5 of 45 (11%) of this group of dogs.

References: Hess et al, JAVMA 217: 1166-1173, 2000; Peikes, Morris, and Hess, JAVMA 219: 203-208, 2001.