What are the symptoms of sweet itch?

Intense itching focused on the mane, neck and tail; lumpy, scaly or inflamed skin; ruffled or rubbed hair; and in severe cases hair loss, bleeding, thickened skin, restlessness and even weight loss from constant scratching.

When is sweet itch season in the UK?

The midges that cause sweet itch are usually active from spring to autumn, and are worst at dawn and early evening. Some badly affected horses show symptoms all year round, and the condition typically becomes more severe each year without management.

Can sweet itch be cured?

No — there is no real cure, but it can be managed effectively. World Horse Welfare recommends a good-quality full-body fly rug, pyrethroid or permethrin-based repellents, stabling at dawn and dusk, and prompt treatment of any flare-ups, with steroids or antihistamines only under veterinary direction.

Do sweet itch rugs work?

Yes — a well-fitting full-body fly rug with neck and belly coverage is one of the most effective defences, because it physically blocks midge bites. Buy at least one spare so rugs can be washed and rotated, and combine the rug with repellent and stable management.

Horse Health

Sweet Itch in Horses: UK Guide

Published 18 July 2026Last updated 18 July 20264 min read

Quick answer

Sweet itch is an allergy to Culicoides midge bites and the UK's most common allergic skin disease in horses, affecting around 5% of the horse population, according to World Horse Welfare. There is no cure — manage it with a full-body fly rug, repellent, stabling at dawn and dusk, and vet support.

Key takeaways

**Sweet itch** is an allergy to **Culicoides midge** bites and the UK's most common allergic skin disease in horses, affecting around **5% of the horse population**, according to World Horse Welfare.
There is no cure — manage it with a **full-body fly rug**, repellent, stabling at dawn and dusk, and vet support.

What is sweet itch?

Sweet itch is an allergic skin reaction to the saliva of biting insects — principally Culicoides midges, though black fly (Simulium) and mosquitos can also trigger it. According to World Horse Welfare, it is the most common allergic skin disease in UK horses, affecting around 5% of the horse population, and is particularly prevalent in some native breeds.

Severity varies enormously: one horse may scratch its tail occasionally, while another rubs itself raw. Without management, symptoms typically become more severe year after year.

Signs to look for

Intense itching focused on the mane, neck and tail — the classic pattern — though badly affected horses rub wherever they can reach
Skin that looks lumpy, scaly, inflamed or hot to the touch
Ruffled or rubbed patches of hair
Hair loss, bleeding and thickened skin from self-trauma
Restlessness; in the worst cases, weight loss

Regular grooming helps you spot skin changes early — and early action is the single biggest factor in keeping sweet itch under control. Your vet can confirm the diagnosis, sometimes using intradermal allergy testing to rule out look-alike conditions, including other allergic skin disease and infections such as mud fever.

Prevention — your main defence

According to World Horse Welfare, prevention is far better than cure:

Measure	How it helps
Full-body fly rug	Physically blocks bites; buy a spare so rugs can be washed and rotated
Repellent	Pyrethroid/permethrin-based products are often most effective; patch-test DEET products first as they can cause soreness in some horses
Stabling at dawn and dusk	Biting midges are most active at dawn and early evening
Mesh screens	Special mesh over stable doors and windows keeps midges out; introduce gradually
Paddock choice	Avoid waterlogged ground and soft mud where midges breed; windswept fields hold fewer midges than sheltered, still ones
Field shelter access	Gives turned-out horses somewhere to escape peak midge times

Treatment and vet options

There is no cure for sweet itch — management is about reducing bites and calming reactions:

Steroids can relieve itching short-to-medium term, but long-term use increases the risk of laminitis — only ever on your vet's prescription
Antihistamines may help but must be given in relatively high quantities — again, only under veterinary advice
Anti-itch shampoos containing oatmeal, antihistamine or local anaesthetic can soothe skin; cold water or ice gives short-term relief
Supplements — research cited by World Horse Welfare suggests omega 3/6 fatty acids (such as flax seed) and nicotinamide-based supplements can reduce itching in some horses

Expect some trial and error — different horses respond to different combinations, so keep notes on what works for yours.

Living with a sweet-itch horse

Start early each spring — rug up and apply repellent before the first bites, not after rubbing starts
Inspect skin daily during the season and treat flare-ups immediately
Keep rugs clean and repaired — gaps and dirty rugs cause rubbing of their own
Plan turnout around midge times — many owners swap to night-time turnout in high summer
Budget for the condition — rugs, repellents and supplements are a recurring annual cost

When to call the vet

Contact your vet if the skin is broken or infected, if itching is severe despite rugging and repellent, or if you are considering steroids or antihistamines. A confirmed diagnosis also opens the door to prescription treatments and a structured management plan.

Sources & further reading

Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.

PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-07-18).

Frequently Asked Questions

What is sweet itch in horses?: Sweet itch is an allergic reaction to bites from Culicoides midges (and other biting insects such as black fly). According to World Horse Welfare it is the most common allergic skin disease in UK horses, affecting around 5% of the horse population, and can affect almost any horse or pony regardless of breed or age.
What are the symptoms of sweet itch?: Intense itching focused on the mane, neck and tail; lumpy, scaly or inflamed skin; ruffled or rubbed hair; and in severe cases hair loss, bleeding, thickened skin, restlessness and even weight loss from constant scratching.
When is sweet itch season in the UK?: The midges that cause sweet itch are usually active from spring to autumn, and are worst at dawn and early evening. Some badly affected horses show symptoms all year round, and the condition typically becomes more severe each year without management.
Can sweet itch be cured?: No — there is no real cure, but it can be managed effectively. World Horse Welfare recommends a good-quality full-body fly rug, pyrethroid or permethrin-based repellents, stabling at dawn and dusk, and prompt treatment of any flare-ups, with steroids or antihistamines only under veterinary direction.
Do sweet itch rugs work?: Yes — a well-fitting full-body fly rug with neck and belly coverage is one of the most effective defences, because it physically blocks midge bites. Buy at least one spare so rugs can be washed and rotated, and combine the rug with repellent and stable management.