Ringworm is a common skin problem in humans as well as dogs. Despite its name, however, ringworm is caused by a fungus, not a parasitic worm. Diagnosing ringworm takes more than just physical examination. A fungal culture must be performed to determine if a skin rash or other dermatological anomaly is caused ringworm. To this end, a small amount of material is obtained from the vicinity of the lesion and placed on a culture medium. The medium is then incubated and examined over the course of 1 to 4 weeks. If fungal growth occurs, the diagnosis is confirmed.
Fungal culture is indicated any time there is a suspicious skin rash or lesion. There are no contraindications to performing this test.
What Does a Fungal Culture Reveal in Dogs?
A fungal culture reveals whether or not a skin lesion is caused by dermatophytes (ringworm fungi). Diagnosing ringworm is important because there is be risk of cross-species infection from animals to humans. Appropriate treatment of affected animals should be instituted immediately and, where applicable, owners should be advised on how to avoid contaminating themselves.
How Is a Fungal Culture Performed?
In order to perform a fungal culture, your veterinarian must pluck hair from the vicinity of the skin lesion and/or gently scrape the skin surface. This hair and skin is then placed on a culture medium that turns from amber to red in the presence of dermatophytes. Initial results may be available as early as 10 days. The sample should be placed on another growth medium and incubated for 10 days – 4 weeks to observe for fungal growth. This is important to identify which dermatophyte species is involved. Since fungi are slow growing; final test results may not be available for up to 4 weeks.
Is a Fungal Culture Painful to Dogs?
The only pain involved is that associated with collection of the hair sample. The discomfort experienced will vary from individual to individual.
Is Sedation or Anesthesia Needed for a Fungal Culture?
Neither sedation nor anesthesia is needed.