Skin and Hair Testing

Here in the lab at Valley Equine, we test for a several different skin complaints using various methods. All testing ideally starts with the same sample – a skin scrape, where the vet uses a blade to scrape skin cells. hairs and any scabs or flaky material from a suspicious area. A small sample of hair, plucked so that it includes the hair roots, is also especially helpful in interpretation. From here, our lab staff perform direct microscopy – where the sample is softened with chemicals and examined under a microscope – and a fungal culture – where the sample is placed onto a special type of agar gel that encourages the growth of fungus, with ringworm reacting with the agar and turning it a deep red colour if it is present.


Ringworm is a very common skin complaint in horses. It is caused by a fungus, and is extremely contagious to other animals. It can be spread through direct contact, but also through tack and grooming equipment. If ringworm is identified in one or more of your horses, it is important to take precautions to reduce the risk of spreading the infection to other animals on the premises.

The first signs of ringworm are usually raised circular patches on the skin with the hair falling out in these areas. Thick, dry scabs will then usually form over these areas.

On the day of submission of a skin/hair sample, you will receive a result telling you whether the sample was microscopically negative or positive for ringworm. If the result is positive, your vet will discuss the treatment options with you as soon as possible. If the result is negative, it is advised to await the fungal culture result 3-4 days after submission. If the fungal culture is negative, it can be confirmed that your horse is not suffering from ringworm. Again, if a positive result is given after culture, your vet will discuss treatment options with you.

We also issue on request negative ringworm certificates to prove fitness to race.

Mites and Lice

We also test for external parasites when performing skin/hair testing. Lice are one of the most common parasites found on the skin of horses. There are two types – biting lice, which feed on the skin cells and hair outside the body; and sucking lice, which pierce the skin in order to feed on the fluids beneath. Lice can usually be seen during a routine examination of the animal, either by yourself or a vet. Lice can be brought in contained in a sealed specimen pot (or similar) for identification.

Mites are most often associated with mange in horses, and cause raised fluid filled bumps on your horse’s skin, along with possible hair loss. More extreme cases of mange can result in widespread scaling and scabbing of the skin, along with intense itching. Diagnosis of mites is usually by microscopy – if enough layers of skin are included in the skin scrape, the mites and their eggs can be clearly seen.