Page 877 - The Veterinary Care of the Horse

NODULAR SKIN DISEASE

VetBooks.ir This condition is also known as eosinophilic granuloma, collagen necrosis and nodular

collagenolytic granulomata. The disease is characterized by raised nodules on the neck,
withers and back, sometimes extending to the chest and abdominal walls (Figures 18.28a and

b).

Figures 18.28a and b Nodular lesions a) on the head and neck; b) in the saddle area

Causes

The cause is unknown but it is thought to be a hypersensitivity reaction. As lesions tend to

develop in the spring and summer, insect bites may be a trigger. Pressure from an ill-fitting or
poorly flocked saddle may cause the lesions to develop in the saddle region.

Clinical signs

The round, raised nodules are:
• 0.5–1 cm ( in) in diameter

• firm to touch

• usually covered by hair

• painless

• non-irritant
• variable in number from one or two to several hundreds

• likely to ulcerate if the lesions are abraded