Please help! Insect bites causing large amounts of edema and pain

[lenapesadie]

My dearly departed Norman would get bites similar to your boy.

I knew it was bites/stings, not a doubt in my mind. I’d first see tiny bumps which would then occasionally proceed to blow up. Areas bigger than a large dinner plate, not perfectly round though. Raised up an inch or two. His were almost always over his ribs.

My other horse would also occasionally get the tiny bites but his got smaller not larger and disappeared within a few days.

I believe it was ground nesting yellow jackets.

[emipou]

Hi! I’ll try my best to update questions. Long day!

He is stalled 24/7 and can’t be turned out for numerous reasons related to health and medical history (mostly because he has history of sand colic - has had two colic surgeries when he was younger, also because he had a digital flexor tendon injury a few years ago and he really loves to pound hard on the ground in turnout- he is extremely happy where he is and gets out for walks or work or hacks daily).
We are attempting to walk now but it’s been painful for him… two people have to slowly guide him to the wash rack. I’ve been doing light walks with him in the walkways where it’s padded and that seems to work best for him. Once he is less painful, I’ll handwalk, then progress to lunging, then up to tack walking (once girth area clears enough)

These episodes typically last 4-7 days depending on how bad. He’s had 4 or 5 episodestotal over the past couple years.

He has all our local vets stumped. They’ve referred to the local hospital and those vets are also stumped.

Vet came back out tonight and ran Serum amyloid A (SAA) test. Normal would be 0-20, he came back 2,528. It basically returns a value on infection and inflammation with no further detail but does provide a baseline that we can check against in a few days to see if he’simproving.

We x-rayed for founder. He’s all good.

Blood work came back great.

Since some of the edema is warm to the touch, vet put him on antibiotics. He is taking that with a light diuretic, steroids, banamine, ulcergard. I think this will break it up.

We’ve known in the past it was insect because a head would form above the main areas of edema, you could literally follow veiny paths of edema down his barrel or neck then the fluid just forms and goes down his body to the lowest point until it disperses. A head would form and a large swelled 3" diameter area around the head. We could break the head off and push fluid out. This has not happened this time yet. We’re still waiting to see. We’re pretty sure he was bit on his left neck below the crest/braid because he started sweating profusely yesterday around the ears, eyes, forelock, butt, and this one spot on his neck. It was very mild weather yesterday and he had a fan on him.

We’ve been taking temps multiple times a day…
Started over 101. Went down to his normal mid 99 range last night. Went back up to 100 range today.
He was 100.1 when I left tonight.

No changes to neighboring stalls. No changes to bedding or food or supplements really, just what supplier has seasonally. The bedding does come in off a truck and sometimes the loads vary, we’ve wondered this in the past.

I keep forgetting that we have one woman at the barn who had this exact same thing happen with her horse at some showgrounds. She thought he would have to be PTS but he was fine after 4 days. Same pain and swelling. And now @2DogsFarm 's account are the only similar accountings. There are no hives and no open sores.

Thanks all for the input, it has given some good food for thought.

I took some photos of him today. I need to remember video of him walking. It does at times look neurological but we aren’t really considering this as a path to go down at this point.

[Qmk77]

Hi there,
I just got the same problem with my gelding. Was wondering if you have any updates? How long did it take him to recover? Any luck witz treatments?
Thank you!

[emipou]

@Qmk77 sorry for the delayed response!

We had an internal specialist out who did a full exam including ultrsounds in 3 places. The conclusion was that his melanomas were wreaking havoc on his lymphatic system anytime anything small happened to his body.

While we didn’t know the exact cause for his last occurrence, we found that banamine for pain/fever, antihistamines, and steroid packs with added diuretics were the meds needed. He was cold hoses 1-2x/day and exercised as much as we were able to without causing pain.