What is ringworm?

Ringworm is a contagious skin condition caused by different species of microscopic fungi known as dermatophytes.

The most common species affecting companion animals are:

  • Microsporum canis
  • Microsporum gypseum
  • Trichophyton mentagrophytes

Ringworm is often spread through unsanitary conditions and is most prevalent in young or immune compromised patients.

Symptoms Of Ringworm

Unlike ringworm in humans, it is often not itchy.

The primary symptom of ringworm in companion animals is circular areas of hair loss, scaly skin and occasionally a ring of reddened skin.

Most common sites of infection are: the face, feet and under the belly.


M. canis is the most common species found and will fluoresce when under a Wood’s lamp. Other species of ringworm will not fluoresce and need to be diagnosed via fungal culture (this can take up to 4-6 weeks).

A history of family members such as children having similar lesions is a good indicator.


Environmental decontamination is the most important mainstay of treating ringworm as spores can live readily in an animal’s environment. This requires removal of all in-contact bedding and heavy bleaching of all surfaces.

Topical treatment of single lesions with Malaseb® or antifungal creams is often effective. For more generalised ringworm, antifungal tablets may be prescribed. Treatment needs to continue for a minimum of 2 weeks after lesions has resolved to ensure all spores are killed.