Reaction to Z-itch?

[squishypony]

We’ve treated my horse with Z-Itch on 22/05 due to an outbreak of lice at the yard. 23/05 his skin has come out in hives, and he’s had severe muscle spasms in his hind end to the point he could hardly walk. We’ve had the vet who is a bit baffled, taken bloods and waiting on those. Vet wondered if he’d fallen but has gone off the idea. Considered tetanus but no cuts and he’s up to date on jabs. Can’t see it being sycamore poisoning as these are only symptoms. He seems fine now but would like to know what has caused it! I’m going to get physio out and obviously waiting on bloods but wondered if anyone has had anything similar when applying Z-Itch or similar?

 

[Gloi]

The only reactions I have seen is a bit of a skin reaction where it has been applied, which soon went down .
Hope your horse is okay.

 

[Glitter is Fun]

Is there any way he could have got an overdose?

"Overdose of permethrin
Toxic signs in mammals are tremors, hyperexcitability, salivation, choreoathetosis[twitching] and paralysis. The signs disappear rapidly and the animals recover, generally within a week. There is no specific antidote but symptomatic therapy can be given if considered necessary."