large lumps on my horses back/side?

[Uraeus]

I noticed today that my horse has three large hard lumps on his back and side,Near his withers. One is about the size of a £2 coin, the other is a large oval shape and the 3rs is a bit bigger. They don't bother him, he's 2 so not ridden and they don't seem to hurt. They've appeared over night and I'm thinking maybe an allergic reaction to fly bites? Iv been looking at a lot if threads but most of them describe clusters of small hard lumps like peas, but these are much larger. Has anyone had anything like this before?

 

[ROMANY 1959]

My sons tb mare had several large two pound coin size lumps on loins and belly weekend, fly bites , when I parted hair they each had little yellow head, I just put allo Vera on and let them go down, nearly all gone today.

 

[ebonyallen]

I do agree was going to say fly bites, my girl comes in with great big lumps and they do go down when treated, I use Red Rum roll on arnica and tea tree, works a treat.

 

[Shysmum]

sounds like fly bites - mutant flies. Seen some awful bites over the last few years. x

 

[StormyMoments]

fly bites

 

[horsemadelsie]

I have a midge bite on my leg exactly like this