Dermatophytosis

Dermatophytosis

Dermatophytosis in dogs, commonly known as ringworm, is a contagious fungal skin infection that affects the hair, skin, and sometimes nails. Despite its name, ringworm is not caused by a worm but by a group of fungi called dermatophytes, most commonly Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes. This condition can affect dogs of all ages, but is more common in puppies, older dogs, or pets with weakened immune systems. Because ringworm spores are highly resilient and can survive in the environment for months, early detection and proper hygiene are essential to prevent their spread to other pets and humans.

Dermatophytosis usually develops when fungal spores come into contact with a dog’s skin or coat, especially through small wounds, scratches, or areas of broken skin. Warm, humid conditions and poor grooming can increase the risk of infection. The fungi feed on keratin, a protein found in hair and skin, leading to hair loss and skin damage. Dogs that live in crowded or unsanitary conditions, have frequent contact with other animals, or are under stress are more susceptible to dog fungal infections like ringworm.

The most common symptoms of dermatophytosis in dogs include circular patches of hair loss, redness, scaling, and crusting on the skin. These lesions often appear on the face, ears, paws, and legs, but can spread to other parts of the body if left untreated. The affected areas may look like bald spots with dry, flaky skin in the centre and raised, inflamed edges. Some dogs may experience mild itching, though many cases are not itchy at all. In severe or long-standing infections, the skin may become thickened, discoloured, or develop pustules due to secondary bacterial infection.

Veterinarians diagnose dermatophytosis using several techniques. A Wood’s lamp examination (a special ultraviolet light) may cause infected hairs to glow green, helping identify the presence of certain fungal species. Microscopic hair examination, fungal culture tests, and PCR testing can confirm the diagnosis and determine the specific type of fungus involved. In some cases, a skin biopsy may be recommended to rule out other skin conditions such as mange or bacterial dermatitis.

Treatment for dermatophytosis in dogs typically involves a combination of topical and oral antifungal therapies. Mild infections can often be treated with antifungal shampoos, creams, or ointments containing miconazole, ketoconazole, or chlorhexidine. For more extensive or stubborn infections, veterinarians may prescribe oral antifungal medications such as itraconazole, fluconazole, or griseofulvin to eliminate the fungus from within the hair follicles. Treatment usually continues for several weeks after the visible lesions disappear to prevent recurrence.

In addition to medication, environmental management is crucial because ringworm spores can live on bedding, brushes, furniture, and carpets for long periods. All contaminated areas should be cleaned and disinfected regularly using diluted bleach or veterinary-recommended antifungal cleaners. Bedding, collars, and grooming tools should be washed frequently in hot water. Pet owners should also minimise direct contact with infected dogs until treatment is complete, as ringworm can spread to humans, especially children and individuals with compromised immune systems.

To support recovery, maintaining a strong immune system through proper nutrition, regular grooming, and stress reduction is vital. Dogs that have recovered from dermatophytosis should continue to receive routine skin and coat checks to ensure the infection does not return. Preventing overcrowding, improving hygiene, and promptly addressing any skin injuries can greatly reduce the risk of fungal infections.

With prompt veterinary care, most dogs recover fully from dermatophytosis without lasting effects. However, untreated infections can spread quickly and affect other pets and humans in the household. Responsible pet care, early diagnosis, and consistent treatment are key to keeping your dog’s skin and coat healthy and preventing the spread of dog fungal infections like ringworm.