Diagnosing Yeast Infections in Dogs

Dog Breeds

It can be rather difficult to diagnose this yeast infection in dogs. The initial database for a dog presenting with severe itchiness and other signs of a cutaneous yeast infection includes a complete history and physical examination, together with sampling of affected areas of skin.

Read More >

Introduction

Yeast infections in companion dogs usually first show up as intense skin itchiness (called pruritis), with accompanying scratching and biting at affected areas. The most common causative organism is Malassezia pachydermatis. It can be rather difficult to diagnose this fungal/yeast infection.

How Yeast Infection Is Diagnosed in Dogs

The initial database for a dog presenting with severe itchiness and other signs of a cutaneous yeast infection includes a complete history and physical examination, together with sampling of affected areas of skin. Direct impressions can be taken by pressing a glass slide onto the skin sores, or by pressing acetate tape to the lesions and then applying the tape to the surface of a glass microscope slide. These samples are examined microscopically, with or without specific staining processes, using high power or oil immersion to identify round-to-oval budding forms of yeast that indicate the presence of Malassezia. Samples of waxy debris from infected ears can be taken with a cotton swab, rolled on a glass slide and examined in the same way to identify yeast, bacteria, mites or other possible causes of the dog’s condition. Skin scrapings and bacterial or fungal culture on specific growth media are used to rule out other bacterial or fungal organisms and certain external parasites, such as Demodex mites.

Skin biopsies can be taken and examined by a process called histopathology. Unfortunately, while histopathologic findings may suggest the presence of Malassezia, they are not always diagnostic. Various types of allergy (hypersensitivity) tests and food allergy trials can be used. Systemic diseases and overall organ health can be assessed by routine blood work (complete blood count and serum biochemistry profile) and urinalyses. More advanced tests are available to assess endocrine function, among other things.

Special Notes

If a dog’s ears are infected, it is extremely important to assess whether the eardrums (tympanic membranes) are intact before any liquids, gels, cleansers or other medications are applied, to prevent potentially serious damage to structures of the middle and inner ears.

Treatment Options

Symptoms and Types