Horse Sweet Itch: Managing a Chronic and Distressing Allergic Condition

Sweet itch is an intensely itchy allergic skin condition in horses caused by hypersensitivity to midge bites. Without management, affected horses suffer significantly throughout summer months.

Key Facts

Sweet itch (insect bite hypersensitivity, IBH) affects approximately 5% of horses in the UK
It is caused by an immune hypersensitivity reaction to proteins in Culicoides midge saliva
Affected horses rub mane and tail areas until the skin is raw and hairless — causing secondary infection
The condition is seasonal, peaking when midge activity is highest (spring and summer)
Management involves midge avoidance (stabling at dawn and dusk), full-body sweet itch rugs, and antipruritic medication
Genetic predisposition exists — certain breeds and bloodlines are more commonly affected

Welfare Considerations

Sweet itch causes intense, unrelenting pruritus (itch) that drives horses to rub themselves raw. The suffering is continuous throughout the midge season — horses cannot escape the itch without effective management interventions. Self-trauma leads to open sores, secondary infection, and lasting damage to mane and tail. The psychological component — the constant drive to scratch — means affected horses cannot rest comfortably or concentrate on work. Welfare-centred management prioritises prevention through rigorous midge avoidance rather than reactive treatment of already traumatised skin.

What You Can Do

Stable sweet itch horses between 4pm and 9am — peak midge activity times
Use a properly fitting, full-coverage sweet itch rug during high-risk periods
Apply veterinary-recommended insect repellents appropriate for equine skin
Ask your vet about antipruritic medication for severe cases during peak season
Avoid breeding from severely affected animals to reduce genetic transmission of susceptibility