Moderate

Sweet Itch (Insect Bite Hypersensitivity)

Sweet itch is an allergic reaction to the saliva of biting midges (Culicoides). It causes intense itching along the mane, tail, and belly, leading to self-inflicted hair loss and skin damage. It is a lifelong condition managed, not cured.

Symptoms to watch for

Vigorous rubbing of mane, tail, and belly midline

Bald patches and broken hairs along the crest and dock

Thickened, scaly, or weeping skin

Restlessness at dawn and dusk

Open sores in severe cases

Symptoms peak in spring and summer, resolve in winter

Common causes

  • Allergic reaction to Culicoides midge saliva
  • Genetic predisposition (Icelandic horses, Welsh ponies, Friesians at high risk)
  • Wet, low-lying pasture near standing water
  • Dawn and dusk midge activity

Prevention

  • Stable horses from dusk to dawn during midge season
  • Use a fitted sweet-itch rug (full-body fly sheet) with neck and belly cover
  • Apply long-acting fly repellent containing permethrin daily
  • Install fine-mesh fly screens on stable windows
  • Use stable fans — midges are weak fliers and cannot fly in moving air
  • Avoid pasture near standing water, ponds, or muck heaps
  • Move at-risk horses to drier, higher pasture in summer

What to do

  1. 1

    Bathe affected areas with a soothing medicated shampoo to remove crusts.

  2. 2

    Apply prescribed corticosteroid cream to inflamed patches.

  3. 3

    Use omega-3 supplements (linseed oil) to reduce inflammation.

  4. 4

    Treat secondary skin infections with vet-prescribed antibiotics if needed.

  5. 5

    Maintain rug coverage 24/7 during peak season.

  6. 6

    Document patterns in a diary to refine the management plan.

When to call the vet

Pick up the phone if…

Call your vet if open sores develop, if the horse appears systemically unwell, or if standard management is not controlling the itching. Severe cases may need oral steroids or referral for immunotherapy.

Related topics

Low severity
Mud Fever (Pastern Dermatitis)
→
High severity
Equine Asthma (RAO / COPD)
→

Catch problems early with HorseCare

Daily health logs, vital sign tracking, and AI symptom analysis — built for serious horse owners.

Download on the App Store

Educational content only. Not a substitute for veterinary advice.