Ringworm in dogs – how to spot it and treat it

Q: My three-year-old Jack Russell may have a skin problem. He has lost hair in 
places on his face and ears; 
in patches that look rather like red-purplish bruises. He also 
has another patch on his chest, near his “arm pit”. What could cause this?

A: From what you describe 
I would suspect your dog 
may have contracted ringworm. Ringworm is characterised by circular areas of hair loss, with dry scaly skin in the centre and a red ring at the outer edges. The affected areas tend to increase in size gradually. 
In dogs, ringworm shows up most frequently on the face, ears, legs, 
tail and paws.

Ringworm in dogs is a fungal infection, not a worm

The name is confusing because ringworm in dogs has nothing to do with any worm but is caused by a fungal infection. The vast majority of the cases we see in dogs are caused by three species, Microsporum canis, Microsporum gypseum or Trichophyton mentagrophytes. Ringworm can also infect any 
animal with an epidermal layer of skin, particularly cats, rabbits, horses and cattle, as well as humans.

The signs of ringworm can easily be confused, however, with a number of other skin disorders, including localised demodectic mange, follicular skin infections and other external parasites.

Visit the vet

You would be advised to let your vet examine the dog so that they can make a more accurate diagnosis and recommend treatment. The vet may need to take a sample of skin from around the infected area(s) and examine this for parasites and/or culture the sample to identify the cause of the infection.

If the problem should turn out 
to be ringworm, then unless there 
is some deficiency in the dog’s 
immune system, most cases will 
heal on their own within a couple 
of months. Your vet, however, will be able to prescribe some form of anti-fungal, antibiotic treatment that will accelerate recovery and help avoid any further spread of the infection.