First, welcome to YT
!
The pic does look an awful lot like pyoderma (staph intermedius). Most Vet Dermatologists treat staph with Simplicef x 3 weeks (or 4 weeks). Other antibiotics often do nothing for pyoderma...and you end up medicating them again and again, to little avail. Do they itch in those red areas, btw, or can they not reach them? Do they itch anywhere else (ears, armpits etc)?
It sounds like these symptoms developed around late winter/early spring - when pollens may have been starting in your area. It's a little odd though, that allergies would start for both of them at the same time. So, that coincidence does make one wonder if this is something contagious.
I can tell you from experience that when things recur w/ the skin like this, it is SO helpful to see a Vet Dermatologist - they can probably diagnose this after 1 visit, as skin is their specialty. If it is pyoderma, it's secondary to something else (ie, allergies, or an illness of some kind)...and a vet derm is the best qualified person to walk you thru dealing with where to go from here
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