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“What Is That Crusty Spot on My Pet’s Skin?” by Dr. Julie Yeager

Jul 07, 2014

imagesRU9AU0FDDermatophytosis (ringworm)

“What is that crusty spot on my pet’s skin?”

Skin problems are a common concern for many of our patients.  Skin issues may be due to a number of causes, however ringworm, or dermatophytosis, is an infection that we see frequently and can occur in almost any species of mammal.

What is it?

Despite its common name, ringworm, dermatophytosis is actually a fungal infection that occurs in hair follicles.  The infection causes significant amount of inflammation in the surrounding skin and tissue.

What does it look like?

Affected areas of the skin may be red and slightly thickened.  There may be mild to severe hair loss as well as flaky crusting.  It may affect a relatively small area or may grow to involve a large area or several areas along the skin.  Less commonly, an animal may be a carrier and carry the organism on its skin, but not develop any skin lesions.  These are often only diagnosed if other animals or people in the house hold become infected from the carrier.

Who can get it?

If your pet is a mammal, it can potentially get ringworm.  Animals from dogs and cats to guinea pigs, rats, and rabbits are included in this list.  It is seen with most frequency in young animals whose immune system is not yet mature or animals that have compromised immune systems.  Animals that have recently come from places with lots of exposure to other animals, such as a shelter or pet store may also be at higher risk of developing this infection.   Ringworm is contagious and can be spread between species and can even spread to humans.

How is it diagnosed?

If you suspect your pet may have ringworm or other skin problems, please schedule an appointment to have your pet examined.  The most effective way to diagnose ringworm is with a special fungal culture called a DTM.  Samples are collected from affected areas and placed on the culture medium.  A culture can take up to 3 weeks to become positive as some dermatophyte species are very slow growing.  Several DTM cultures may need to be performed to ensure resolution.

 How is it treated?

There are several treatment options available for ringworm including topical and systemic anti-fungal medication.  The type of medication prescribed will vary depending on the severity of the infection and the location.  Treatment is usually continued for many weeks as ringworm is a hearty organism and can easily return if not completely eliminated.  Disinfecting your pet’s environment is also a critical part in preventing re-infection.  During the treatment period bedding should be washed and changed frequently.  Cages, cage furniture, and grooming equipment should be frequently disinfected.  A 1:10 dilution of bleach works well, however it is very important that bleach fumes be kept away from your pet and that any objected disinfected with the solution be completely dry and odor-free before it is used for your pet again.  While treatment can be a bit labor intensive and lengthy, if proper treatment protocols are followed, resolution is obtainable.