Insect Bite Hypersensitivity (QLD Itch): Effective Management

Dr Mikarla Poole

Horse being annoyed by biting flies

Every summer, we see the same pattern 

The weather warms, the humidity rises… and horses that were previously comfortable begin to itch. It often starts subtly rubbing the tail, scratching the mane, a little hair loss along the belly. Then, for some horses, it escalates quickly into intense irritation, skin damage, and ongoing discomfort. This is commonly Insect Bite Hypersensitivity (IBH), AKA Queensland itch, one of the most challenging conditions we manage on the Sunshine Coast. 

What is Insect Bite Hypersensitivity?

IBH (also known as sweet itch) is a hypersensitivity reaction to biting insects, especially midges (Culicoides spp.). Affected horses develop an allergic response to midge saliva, resulting in significant pruritus (itching). 

These insects are: 

• Extremely small  

• Most active in warm, humid conditions  

• Most active at dawn and dusk

• Common in coastal regions such as the Sunshine Coast and Southern Queensland 

Common signs

IBH horse with wheals on the thorax

Severity varies between individuals, but common signs include: 

• Rubbing of the mane and tail  

• Hives/wheals

• Hair loss along the crest, tail head, and ventral midline (under the abdomen)  

• Thickened or crusted skin in chronic cases  

• Secondary wounds from persistent rubbing and self-trauma, further complicating case management. 

IBH is not just a cosmetic issue, the ongoing irritation and inflammation can significantly impact comfort, behaviour, and performance. 

Common clinical signs of IBH including rubbing at the tailhead

Why management can be challenging 

One of the most important things to understand is: 

No single treatment is sufficient on its own. 

Successful control relies on reducing allergen exposure while managing the inflammatory response.

Instead, effective management combines: 

• Insect avoidance  

• Barrier protection  

• Skin care  

• Medical therapy when required  

Consistency is critical, particularly during high-risk seasons. 

Management: A practical, multimodal approach

Horse with rug and flyveil for protection against biting insects

1. Insect avoidance – the foundation of control

Minimising exposure to Culicoides (biting midges) is the most effective intervention. 

Typical strategies include: 

• Regular application of insect repellents containing permethrin. This includes reapplication as directed, particularly in humid or high-exposure conditions  

• Targeting high-risk areas such as the mane, tail, ventral abdomen (belly), and ears 

Protective rugs designed for Queensland itch can also be highly effective. These: 

• Provide a physical barrier  

• Often incorporate insect-repellent properties  

2. Timing of turnout

Biting midges are most active at dawn & dusk.  

Where possible: 

• Stable or yard horses during these periods further from active insects 

• Turn out during the middle of the day when insect activity is lower  

Even small changes in timing can significantly reduce allergen exposure. 

3. Environmental management

Simple environmental adjustments can help reduce insect burden: 

• Use of fans in stables (midges are weak fliers)  

• Avoid turnout in low-lying, damp, or still areas  

• Select paddocks with good airflow and minimal standing water 

4. Nutritional support

Skin health plays an important role in resilience. 

Dietary strategies may include: 

• Supplementation with omega-3 and omega-6 fatty acids 
  → Supports skin barrier function and coat condition  

While not a standalone treatment, this can contribute to overall management. 

5. Managing flare-ups and skin lesions

When itching occurs, early intervention helps prevent escalation. 

Washing horses in shampoos that protect and nourish is important

Topical care may include: 

• Application of soothing preparations or barrier to reduce irritation  

• Gentle cleansing of affected areas to remove crust and debris 

• Protection of damaged skin and effected areas to reduce further trauma  

In more severe cases secondary infections develop and veterinary treatment is required. 

When veterinary treatment is needed

Some horses require medical support to remain comfortable. 

This may include: 

• Anti-inflammatory medications such as corticosteroids (topically and/or systemically) to reduce pruritis 

• Management and treatment of secondary bacterial infections of the skin 

• Development of a tailored management plan for long term strategies  

Importantly: 

Medical treatment is most effective when combined with consistent environmental and preventative management. Early and proactive management leads to better outcomes, starting control measures before peak insect season and before clinical signs become severe. 

With early recognition, consistent insect control, appropriate environmental management and veterinary support when needed. Many horses can be kept comfortable throughout the season. 

Book an Assessment

If your horse is showing signs of itching or you would like to develop a proactive management plan, our team can help guide a structured approach tailored to your horse. 

Contact Sunshine Coast Equine Hospital to discuss your horse or arrange an appointment.