Page 857 - The Veterinary Care of the Horse

• Avoid riding through dense patches of tall stinging nettles on overgrown bridleways.

• Always test topical preparations such as fly repellent and shampoos on a small area of
VetBooks.ir • skin first and wait 24 hours before treating the whole horse.

Avoid using biological detergents to wash numnahs and girths of sensitive horses.

EXERCISE

The wheals sometimes increase in size if the horse is worked and becomes warm. In these
cases, exercise should be avoided especially if the wheals are under the bridle or saddle.

Prognosis

Although the cause often remains undiagnosed, in many cases the signs disappear within a
few hours or a couple of days without treatment. However, there are horses that are

persistently troubled by this condition and it prevents them from engaging in their normal
work. Pinpointing the cause is often difficult and eliminating the allergen may not be

possible. In this case the horse can be kept on long-term maintenance corticosteroids, but this
has the risk of side effects including laminitis. If the condition is recurrent, the prognosis is
guarded although many cases gradually resolve with time, even though the cause is never

established.

PEMPHIGUS FOLIACEUS

Pemphigus foliaceus is an autoimmune skin disease. Affected horses and ponies have an
abnormal immune reaction and produce antibodies against components of their own skin.

Appaloosas may be predisposed; the condition has been identified in both adult horses and
those younger than 1 year old.

Causes

Very often there is no obvious cause. On occasions it may be triggered by certain medication,
vaccines or stress, e.g. pregnancy.

Clinical signs

These may be mild or severe. They include:
• eruption of vesicles (blisters) or pustules which quickly burst