Every year in spring, it’s that time again. All owners of horses with sweet itch ask themselves: “When is the right time to put the anti mosquito blanket on?” You need to weigh up how much longer you can leave the horse uncovered, or whether waiting too long might already be setting it up for a bad start to the itch season.
Author: Marie-Theres Conen, Sportsfreund Studios
Why Do Icelandic Horses Get Sweet Itch? Causes & Triggers
Sweet Itch, also known as Insect Bite Hypersensitivity (IBH), is the most common allergic skin disease in horses. It manifests as a chronic, recurring, seasonal dermatitis. This is a Type I immediate contact allergy, triggered by a hypersensitivity reaction to salivary proteins from midges, particularly those of the genus Culicoides.
Especially often are exported Icelandic horses affected. One possible reason is that Culicoides midges do not exist in Iceland, so horses born there do not develop immunological tolerance to the salivary proteins.
While the trigger is known, it remains unclear why only some horses react allergically. Therefore, it is especially important to recognize the first signs early in order to help the horse quickly and keep the course of Sweet Itch as mild as possible.
Sweet Itch-Triggering Midges: Which Species Endanger Your Horse
Sweet Itch, also known as Insect Bite Hypersensitivity (IBH), is the most common allergic skin disease in horses. It manifests as a chronic, recurring, seasonal dermatitis. This is a Type I immediate contact allergy, triggered by a hypersensitivity reaction to salivary proteins from midges, particularly those of the genus Culicoides.
These biting midges prefer habitats with dense woodland vegetation or peat bogs, as well as warm, humid climates with low wind speeds. Their main flight season lasts from April to October, during which they are most active at dawn, dusk, and sometimes even at night.
Emergence Times of Culicoides
- Their activity often begins with the first warm days of spring (from ~10–12 °C).
- In Germany, this depends on temperature and humidity, usually starting in March.
- Peak activity: June to September (the warmest months).
- End of activity phase: November.
Life Cycle of a Culicoides Midge
- Eggs are laid in moist soil, organic material, or water.
- Larvae develop in 2–4 weeks (depending on temperature).
- Lifespan: 2–4 weeks.
- No adult midges survive the winter, but the larvae overwinter in moist soil.
That’s Why We Start Blanketing Earlier:Shorter, mild winters favor midge populations. Larvae hatch and develop earlier when the soil doesn’t freeze in winter. The longer the warm period in a year, the more generations can develop. The same applies in autumn: The later it gets cold, the longer midges can emerge.
When to Put on a Sweet Itch Rug in Spring?
- Culicoides midges become active at temperatures of 10–12 °C.
- Especially when it’s calm and dry.
- This usually happens from late March onward.
Sweet Itch in Horses: These Spring Symptoms Show When You Need to Blanket
Unfortunately, it’s generally difficult to predict exactly when the first swarms of midges will appear in different parts of Germany, as temperatures vary by region. That’s why it’s important to observe the symptoms in your horse with Sweet Itch.
Important: Don’t wait for the first bloody spots before blanketing! If your horse is already visibly rubbing itself, you’re already too late—your horse is already experiencing its first allergic flare-up.
Early Symptoms of Sweet Itch::
- A tangled mane or tail
- Excessive grooming spots all over the body
- Suspicious enjoyment during grooming: Your horse signals that grooming a particular spot feels especially good.
Of course, this only applies in comparison to the previous weeks. If your horse looks scruffy all winter because it’s been grooming with its friends, or if it always makes a long upper lip when you scratch its neck, for example, that’s not immediately a sign of Sweet Itch. It’s just about comparing it to its normal state.
If any of these symptoms occur more than once in a row in spring, as temperatures rise, reach for the Sweet Itch Rug immediately.
The Best Sweet Itch Rug for Icelandic Horses: Spring Tips
Yes, early blanketing isn’t fun. But horses prefer wearing a good rug to scratching themselves into a frenzy.
With possible temperature fluctuations, make sure you have a breathable rugthat doesn’t get too heavy or cold during brief rain showers. It should also prevent your horse from overheating on the first warm days.
When it comes to fit, keep in mind that Icelandic horses have a thicker winter coat and may be more voluminous, so snugly fitted rugs might be too tight. A Sweet Itch Rug with stable, elastic fabric is ideal.
In frequently changing weather, depending on how sensitive your horse is, you can also skip the rug. Heavy rain and wind deter midges, or they can’t fly through such conditions. Related article: What Should a Sweet Itch Rug Be Capable Of?
Do you need assistance or advice?
- Frequently Asked Questions (FAQ): Here you’ll find more information about our Sweet Itch Rug.
- Need personal advice? Schreib uns ekzem@sportsfreund-studios.com
For sensitive horses in changing weather conditions, we recommend::
- A well-fitted Sweet Itch Rug with built-in rain protection (though it should be removed during longer periods of fair weather, as it is less elastic and breathable),
- Or combining a Sweet Itch Rug neckpiece with your Rain RugSince most Icelandic horses have plenty of mane, a wet neck cover won’t bother them. This way, they’ll have full rain protection on the rest of their body and overall midge protection.
So: Check the weather forecast and pay attention to your horse’s signals. Don’t blanket just because everyone else at the barn is bringing out their fly sheets—every horse has different needs, and you should learn to read them.
Sources: https://phaidra.vetmeduni.ac.at/api/object/o:3341/get
https://flexikon.doccheck.com/de/Culicoides
https://de.wikipedia.org/wiki/Culicoides
