Help! Weird lumps on horses back :(

[xxxloz123]

Hello,
I apologise in advance for the following essay...
My horse had been getting some strange lumps appearing ( only after being ridden ) In his saddle area, They were very small pea sized lumps, that would go completely with in 30 minutes, I got some opinions from others and agreed that they were heat lumps. This was about a month ago now. As of about 2 weeks ago he has been getting these insect bite like lumps appearing on his left side, across his back, mainly his saddle area again. These would come and go, and would be worse one day than the other, but this week has been the worst and im now worried. Today they had spread down his belly and onto his croup. I took some photos yesterday, And I have one photo from today, although hes covered in cream, you can still make out where they are. Im not sure how well you will be able to see the lumps, but if anyone has any suggestions as to what could be causing this I would appreciate any advice He has the vet coming tomorrow aswell.

This is today

 

[xxxloz123]

Should have mentioned, these large lumps are not just after hes ridden, I have not rode him since they got like this.

 

[DuckToller]

Just a thought - have you washed his numnah/saddle cloth recently? Could be an allergic reaction to the washing powder. The ones spreading backwards might be caused by the substance being spread as you groom him.

Hopefully your vet will have some ideas too - although often it is trial and error with these allergic reactions.

 

[xxxloz123]

No the one I had been using was brand new :-S I have washed it now as someone suggested blocked sweat glands and advised to keep his numnah really clean, I have not ridden him since though, and they have got worse

 

[claireandnadia]

Nadia had a similar thing last year, they were insect bites.

 

[calon]

these are quite common the name i forget sorry they may or may not just go away kep things clean and wash off with water maybe dilute hibby scrub after exercise vet may give you some shampoo for it a sit can be a fungus type thing x

 

[xxxloz123]

Thank you for your replies, had the vet and he has urticaria, Very mild. I just need to cold hose it after excersize. We are not sure what has caused it, possibly fly bites. So he is in his fly rug Hopefully it will go soon.