By Michelle Knowles
When then skin is disrupted by disease, hormonal upsets, and sometimes injury, M. pachydermatis can become overgrown on the skin and cause itching, discomfort, hair loss and, in many cases, secondary infections.
Flews, folds of skin, groin and other sebaceous zones tend to get scabby. The skin thickens, may be pink, red or has progressed to the black or gray leathery stage, and the crusts can be maddeningly itchy. There might also be a strong odor that exudes from the skin. Hair loss may occur, and the coat may look patchy and greasy, and/or scaly.
Overgrowth of M. pachydermatis is caused by some kind of disruption in the skin that throws off the balance of bacteria to fungus ratio on the surface of the skin. There is usually a triggering event that causes the loss of the skin’s defenses. Things like allergies, external parasites, forms of cancer, immune system breakdown, and extended use of antibiotics or steroids can all be culprits in creating the conditions of yeast overgrowth.
A study done in 2005 found that dogs with recurring M. pachydermatis can re–catch the yeast as it is carried by the owner on their skin and in some cases from the health care workers, vets, technicians and groomers that handle the pets. Good salon and personal handwashing hygiene are essential in keeping this issue under control.
The veterinarian uses a few different methods to diagnose M. pachydermatis. Skin scraping is a method in which a sharp blade, such as a surgical scalpel, is used to scrape the surface tissue of the affected area and placed on a slide to be examined under a microscope. The sample is then treated with a solution that destroys everything but the fungal cells so they can then be identified. Acetate tape can also be used to pick up loose crusts on the surface of the skin which can then be examined for the yeast and other bacteria that may be present. In some cases, a biopsy can be taken and sent to a lab so it can be determined what exactly is causing the skin issue.
While internal anti–fungal medications may be prescribed by the vet, especially in the case of yeasty ears, there are steps you can take as a groomer to help alleviate discomfort and support the skin in a way that helps control yeast growth and brings the skin back into balance. It is important to remember to refrain from discussing internal medication with the client; this is practicing medicine without a license and could lead to litigation and other legal issues.
Diagnosis by a qualified veterinarian is very important. Symptoms are often similar for both bacteria and yeast, and if the wrong treatment is given, the infection can become worse. There are several treatment options depending on all the underlying factors and if there are secondary infections present or a systemic condition that is exacerbating the overgrowth.
Here are a few steps groomers can take to help alleviate the symptoms associated with this condition:
1. Clay masks that draw in oils and neutralize the pH of the skin are the first step in reducing inflammation and preparing the skin to receive the cleanser.
2. Cleansers should contain antifungal properties, the main ingredient being miconazole, ketoconazole, climbazole or elemental sulfur, with or without chlorhexidine. This needs to sit on the pet for at least ten minutes to be maximally effective.
3. After rinsing well, use a mineral conditioner or a thinned down version of a neutral conditioner with minerals added as a skin barrier protectant.
Depending on the severity of the infection, this skin regimen may need to be done as often as every three to five days. If not severe, a good rule of thumb is to have the client come in once per week for treatment, keeping in mind that sessions should continue for ten days after the skin visibly recovers. Document all products that are used and take pictures of all sides of the pet to be kept in the file so that you, the client and the supervising veterinarian can track the progress of the treatment.
This issue is a common problem that groomers deal with regularly, but armed with a correct diagnosis from the vet, it is a very controllable condition in which you can give comfort and health back to the skin of your four–legged pet friends. 
References
Bajwa J. (2017). Canine Malassezia dermatitis. The Canadian veterinary journal = La revue veterinaire canadienne, 58(10), 1119-1121.
Bond R. Advances in Veterinary Dermatology. Vol. 4. Oxford, UK: Blackwell Science; 2002. Pathogenesis of Malassezia dermatitis; pp. 69–75.
Bond R, Saijonmaa-Koulumies LEM, Lloyd DH. Population sizes and frequency of Malassezia pachydermatis at skin and mucosal sites of healthy dogs. J Small Anim Pract. 1995;36:147–150.
Morris D. O. (2005). Malassezia pachydermatis carriage in dog owners. Emerging infectious diseases, 11(1), 83-8.
Nakabayashi ASei YGuillot J Identification of Malassezia species isolated from patients with seborrhoeic dermatitis, atopic dermatitis, pityriasis versicolor and normal subjects. Med Mycol 2000;38337- 341