Ringworm in dogs

MetPet.com Staff Writer

Although it sounds like a parasite, ringworm is actually a fungal disease caused by microscopic organisms.  The name comes from the round skin lesion that is characteristic (although not always present) in an infected dog.  As the infection grows, it spreads in a circular pattern which looks like a ring.  It is the most common fungal disease in dogs and the same organisms can also infect humans. 

Several different organisms can cause ringworm:  Microsporum canis and Trichophyton mentagrophytes are transmitted from infected animals.  Microsporum gypseum is transmitted through infected soil.  It appears to be most common in regions with warm, moist climates.

Symptoms include patchy hair loss, dry flaky skin, reddened or irritated skin or the tell-tale circular rings.  A dog can also be infected and not show any symptoms although he can be a carrier (as can cats) and infect others. 

Diagnosis is made using a blacklight or with skin scrapings examined under a microscope or with a fungal culture (skin scrapings applied to a petri dish with a growth media to see if a fungus grows). 

Treatments include medicated shampoos with iodine or chlorhexidine as the active ingredient or an oral antifungal medication.  A natural treatment booster is sunshine on your dog's skin as the fungus prefers a dark, moist growing surface.