Canine Ringworm, A guide to Dermatophytosis

Canine ringworm is a skin infection caused by a collection of organisms known as Dermatophytes (skin fungi). The interesting fact about this condition is that ringworm is not actually caused by worms. In fact the infection that develops is not even ring shaped and for that reason the condition is normally more accurately described as Dermatophytosis.

The Dermatophytes that cause the ‘ringworm’ are not the only skin fungi that can lead to the characteristic skin infection. In fact there are several other species of fungus that can cause the condition including Microsporun canis, Microsporum gypseum and Trichopyton mentagrophytes. All of these conditions are contagious between people and pets (Ackerman, L. 1995. Owners Guide to Dog Health).

How is Ringworm Diagnosed…? The condition is actually not always that easy to diagnose unless the affected dog (or puppy) has the characteristic rash. Problems with diagnosis develop when the rash has not developed. In fact it is quite possible for dogs to be a ‘carrier’ of Dermatophytosis but not show any symptoms. If symptoms do develop then the most common reaction is scaling to the skin, lumps, an inflamed rash and hairless patches.

The condition is normally diagnosed using a ‘Woods Light’. As the hair becomes infected by Microsporum Canis the hair can appear green when examined under the Ultraviolet light. However, the most accurate diagnosis is achieved through a sample of hair being examined under a Microscope or through a fungal culture being taken from the affected area.

The Symptoms of Canine ringworm (Dermatophytosis) can sometimes disappear over time (taking months and years) but the spores associated with the condition can be released into the immediate environment (lasting for as long as 18 months) leading to re-infection and even causing infection to people and other pets that come into contact with the spores.

Canine ringworm is actually not an itchy skin condition but due to bacteria and secondary infections (causing scabs and lesions) this then leads to increased licking and scratching. In some cases a raised nodule can develop due to the bacterial infection attacking the hair roots.

Did you know…? Ringworm can also spread to the nails leading to dry and cracked nails. The condition can be contracted via the soil and from spores that have settled in the carpet or become embedded in the furniture. If your dog or cat has had the skin condition you should purchase new bedding, bleach the hard surfaces and vacuum the carpets.

Treatment for Ringworm in dogs normally involves an anti-fungal topical lotion being applied to the infected hair. The most common treatments are anti-fungal drugs including: Ketoconazole, Griseofulvin and Itraconazole (although all of these can have some side effects).


Ackerman, L. 1995. Owners Guide to Dog Health.

Bleby,J and Bishop, G. 2003. The Dog’s Health from A-Z.

Eldredge, D. Carlson, L. Carlson, D and Giffen, J. 2007. The Dog Owners Home Veterinary Handbook. 4th Ed.

Mash, H. 2011. The Holistic Dog: A complete guide to natural health care. The Crowood Press.

The American Animal Hospital Association Encyclopedia of Dog Health and Care, 1994. Quill. New York.

The Doctors Book of Home Remedies for Dogs and Cats. 1996. Rodale Press Inc, Emmaus, Pennsylvania.

Homeopathic Remedies for Common Skin Problems…

  • Sulphur 30c is one of the most useful remedies for common skin problems as it helps encourage the development of healthy skin. It is particularly beneficial for skin that is hot and itchy.
  • Apis Mellifica 30c can be very beneficial for swollen areas of skin that has become painful.
  • Chamomilla 6c is a great remedy for skin rashes that develop on puppies.
  • Pulex Irritans 30c is useful for allergies that have been caused by fleas.
  • Pulsatilla 30c can be useful for lesions that develop after a dog has eaten a particularly rich food (caused by high fat or protein content).
  • Urtica Urens 6c is the best homeopathic remedy for nettle rash and blotchy red lesions. (Llewellyn, G. 1998. Homeopathic Remedies for Dogs).