TOYTOWN’S chestnut coat is flecked with small white patches, but in earlier photographs of him his coat was unmarked. We asked H&H vet Karen Coumbe to explain

What are the white patches?

“TECHNICALLY, this is called spotted leucotrichia,” says Karen Coumbe. “There is no known cause, nor any effective therapy. Cosmetically they can be a problem for show or cavalry horses, but otherwise they are of no consequence. It’s been suggested the marking may have an immunological cause, but it’s really a benign condition that will not harm the horse.”

Are they dangerous?

GIVEN Toytown’s remarkable performance record with Zara Phillips, including European and World Championship titles, the spots are doing him no harm.

His “go-faster” spots can be thought of as the equine equivalent of freckles, although they are not actually the same thing. In the horse, the hairs go white and, in most cases, the skin, too.

If, when the coat is clipped, the underlying skin has lost its pigment, the coat is more likely to remain that colour for good.

The tendency is for the spots to increase in number but not size. Occasionally, the normal pigmentation may return with time.

Why do they occur?

WHITE hairs or skin can appear in response to trauma, as is seen with freeze-branding. But having spots all over, like Toytown, is not trauma-related, just a benign loss of pigment.

Vitiligo is another term used to describe loss of pigmentation not associated with inflammation or trauma. Typically this manifests itself as pink patches around the face (especially the eyes) of some horses. They tend to appear as a horse or pony ages.

There is also a fading syndrome that affects Arabians, often called “pinky syndrome”, where younger Arab horses develop depigmentation of the skin close to the mucous membranes, such as the eye and mouth, which is thought to be hereditary.

This Q&A was first published in Horse & Hound (14 September, ’06)