I know that PPID can be responsible for worsening skin issues on equines. When I received my saddle donkey 13 weeks ago he was in rough shape. (Undiagnosed PPID being the main problem) He came with terrible rain rot and small rub wounds that were a challenge to heal. Muck-Itch brand spray healed the main areas of rain rot pretty quickly. But there were a few small spots that were either rubbed raw or the insects had literally eaten him raw. The spray did not work and neither did regular wound salve. So....I tried a product called Coat Defense Paste. This stuff covered the wound and stayed on, kept bugs off and stopped any itching. It also cleared up my Haffy mares small rub on her heel that would not go away. If anyone has small spots that are tough to clear up, I would suggest giving this a try. It really works!
Debra and Sam