RingWormInDogs.Net

Since the symptoms of Ringworm are also possibly indicative of several other skin conditions, a veterinarian may have some initial difficulty in forming a positive diagnosis for Ringworm.
To help make this process more definitive, there are several current diagnostic procedures which can help a veterinarian to ascertain if a dog is indeed positively infected with Ringworm.

1. Physical Examination

This is the first, and most basic diagnostic procedure for Ringworm. A veterinarian will perform a thorough physical infection of a dog, and note any lesions that are present. These lesions may be subject to further examination, as to try to discern between a simple skin condition and an actual fungal infection. Though this diagnostic procedure is in no way definitive, it is still a very important part of helping a veterinarian to positively diagnose an infected dog with Ringworm. At this time, a veterinarian may ask several questions of a dog's owner, as to try to determine if there has been any known exposure of the dog to other animals infected with Ringworm.

2. Wood's Light

To help a veterinarian to discover if a dog is infected with the fungus which causes Ringworm, a special type of light may be used. This light is a unique ultraviolet light, which is also called a "Wood's light". Robert Williams Wood first developed this technique in 1903, though it wasn't used in dermatology until 1925. This light is shone at a wavelength of approximately 365 nanometers, and will cause some types of fungus to appear fluorescent when exposed to this light. However, not all fungi will appear flourescent under this light, so this procedure is usually not definitive enough for a veterinarian to disqualify Ringworm as a possible diagnosis when related to skin lesions (or other symptoms associated with Ringworm).

3. Fungal Culture

This diagnostic procedure is usually the most accurate and definitive when attempting to diagnose a dog for Ringworm. However, since this procedure requires a significant amount of time for the fungal culture to mature, it may take up to three weeks. This procedure is performed by removing hair follicles that are in or around the infected lesion on a dog's skin. This is done with a sterile instrument, as to not promote cross-contamination.
Once the hair is removed, they may be initially examined by a specialized veterinarian under a microscope. This can help a veterinarian to positively identify any signs of fungal units on the hair shaft. The hair is then cultured to promote fungus growth in several different mediums. Depending on the quality of the culture, and how reliable the hair sample was, a veterinarian may be to form a positive diagnosis based on a fungal culture, and also will sometimes be able to identify the specific type of fungus causing the Ringworm infection.

4. Skin Biopsy

This procedure is only performed in dogs which have severe skin abnormalities, and dogs which have lesions that are unable to culture for Ringworm fungus. Though this can help to define a true fungal infection with a temporary infection, it is usually not as reliable as a fungal culture.