ISSN 2398-2942      

Microsporum canis


Synonym(s): M. canis




  • Genus: Microsporum.
  • Perfect state: Ascomycetes.

Active Forms

This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Clinical Effects



  • Dermatophytes may be geophilic (soil reservoir), zoophilic (animal reservoir) or anthropophilic (human reservoir).
  • M. canis is zoophilic.


  • Non-parasitic state (including culture).
  • Septate branching hyphae (the mycelium) are produced.
  • Asexual reproductive units (macro- and micro-conidia) are found in the aerial mycelium.
  • Sexual spores (ascospores) are produced.

Parasitic state

  • Hyphae and arthroconidia (also asexual reproductive units) seen.


  • Most commonly direct contact; also fomites.
  • Source most commonly an infected cat.

Pathological effects

  • Dermatophytes are able to hydrolyse keratin and cause some damage to the epidermis and hair follicle. A cell-mediated hypersensitivity reaction is then mounted and the fungus moves away from the site of inflammation to normal skin. This causes the classic ringworm circular lesion with healing at the center and inflammation at the edge.
  • Lesions may occur anywhere on the body.
  • In the cat: often subclinical in adults, generally non-inflammatory except in young kittens. May become generalized in debilitated kittens.
  • In the dog: typically non-inflammatory scaly patches with alopecia. May be kerion when hair follicles rupture.

Other Host Effects

  • Can cause subclinical or inapparent infection in the host animal; it may cause persistent sub-clinical infection in long-haired cats.


Control via chemotherapies

  • Topical: enilconazole Enilconazole , clotrimazole Clotrimazole , tolnaftate, natamycin Natamycin , ketoconazole Ketoconazole although these are not licensed for this use in the dog. Lime sulfur (Lym dip) is a very effective topical.
  • Oral: griseofulvin Griseofulvin + ketonazole (Nizoral tablets), itraconazole (Spornox capsules) or fluconazole (Diflucan tablets).

Control via environment

  • In infected cat colonies, in-contact cats should also be treated.


  • It does prevent development of lesions after challenge.

Other countermeasures

  • Hair should be clipped from affected areas.


This article is available in full to registered subscribers

Sign up now to start a free trial to access all Vetlexicon articles, images, sounds and videos, or Login

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Moriello K A & DeBoer D J (1995) Feline dermatophytosis. Recent advances and recommendations for therapy. Vet Clin North Am Small Anim Pract 25 (4), 901-921 PubMed.
  • Pinter L, Ellis H J, Ciclitira P J et al (1995) Production and use of monoclonal antibodies to Microsporum canis. Vet Microbiol 46 (4), 435-444 PubMed.
  • White-Weithers N & Medleau L (1995) Evaluation of topical therapies for the treatment of dermatophyte-infected hairs from dogs and cats. JAAHA 31 (3), 250-253 PubMed.
  • Sparkes A H, Gruffydd-Jones T J, Shaw S E et al (1993) Epidemiological and diagnostic features of canine and feline dermatophytosis in the United Kingdom from 1956 to 1991. Vet Rec 133 (3), 57-61 PubMed.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!


To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code