Companion Horse Sweet Itch: Chronic Skin Disease and Welfare Management

Sweet itch — hypersensitivity to Culicoides midge bites — causes chronic, intensely uncomfortable skin disease in horses, requiring year-round management to prevent suffering.

Key Facts

Sweet itch affects approximately 5% of horses in the UK; prevalence varies by breed and region
The condition is caused by hypersensitivity to proteins in Culicoides midge saliva — triggered by biting
Affected horses scratch so intensively they cause severe self-inflicted wounds, hair loss, and skin thickening
The itching is described by dermatologists as comparable to severe eczema — causing constant, intense discomfort
Native breeds including Highland, Fell, Dales, and Connemara ponies are disproportionately affected
Management involves midge avoidance, protective rugs, antihistamines, and in severe cases corticosteroids

Welfare Considerations

Sweet itch causes significant and chronic suffering. Affected horses display intense scratching behaviours that cause self-inflicted wounds — rubbing mane, tail, and belly areas against fences, trees, and surfaces. The constant itch drives self-damaging behaviours that continue regardless of wound pain. Horses with poorly managed sweet itch experience this suffering throughout the entire midge season — up to 8 months per year in some climates. Good management requires commitment: keeping horses stabled during peak midge activity at dawn and dusk, using sweet itch rugs covering the whole body, and applying appropriate fly repellents. Desensitisation immunotherapy is available and can reduce hypersensitivity over time.

What You Can Do

Stable affected horses during dawn and dusk midge activity periods through the midge season
Use full-coverage sweet itch rugs from ear to tail to prevent midge access
Work with a veterinarian to develop a management plan including antihistamines or corticosteroids for severe cases
Consider desensitisation immunotherapy for horses with severe, recurrent sweet itch