Strange, painful lumps
My 17.3hh 7yo warmblood x gelding has started coming out in very strange lumps which range from the size of small coins to much bigger (seem to 'grow' over a period of a few days). He finds them very painful to be touched, and the larger ones feel quite hot. They also seem to have a 'head', the smaller ones a small scab, the larger ones have several pinhead like scabs clustered together. They start to decrease in size after a few days (still sore though) until they disappear, leaving an unsightly black hairless patch where the scab was.
He has not had any changes in diet recently, nor covers. He is stabled at night and in the paddock during the day, but have ruled out sawdust in the stable as they started appearing before we started to stable him at night. They seem to be restricted to his barrel/shoulders/whither, he has not had any on his neck, rump, face or legs.
As for being a fungal infection, we did have a horse arrive on the property a few months ago with ringworm (ended up being successfully treated) but this horse was kept isolated and had different tack, brushes, feedbins, etc. Also this horse did not find them painful, just incredibly itchy and they were not as raised. So thinking it is not ringworm!
I am currently washing him every other day with an iodine wash, and spraying them regularly with iodine spray which does not seem to be making a lot of difference. Have also started adding hefty doses of garlic to his feed.
Any suggestions as to what these could be/how to get rid of them would be greatly appreciated, it is becoming very frustrating as I am currently unable to ride him as he has had one pop up underneath where his saddle would be!