Symptoms of Sweet Itch
- This hypersensitivity reaction develops at the site where the insects feed.
- The most common areas are the mane,tail,along the spine and forelock.
- Lesions around the ears and head are also common.
- Other areas affected in more severe cases are the mid-line of the belly, sheath, udder and even legs.
- These lesions are characterised by intense itching, which results in rubbing and considerable self trauma which can cause:
- Broken Hair
- Thickening of the skin
- Flaky dandruff
- Broken skin and sores
- Secondary infections may result
- The horse will swish its tail vigorously and pace up and down.
- Roll more than normal and rub on anything within reach.
- They may sit like a dog and propel themselves around to scratch the top of their tail and also drag themselves along the ground to scratch their belly.
- Lethargy with frequent yawning and a change of temperament.
Cause
Sweet-itch is a hypersensitivity reaction to specific allergens (protein molecules) in the saliva of species of Culicoides biting midges. This results in an immune-mediated production of inflammatory cytokines resulting in swelling and intense itching of the skin.
