Unknown Skin Problem

*** VET ONLY *** Hi can anyone help advice? Dog is 8. Shes a weechon (Bichon X Westie) No change to food or shampoos etc. She had a ear infection month ago so could this be a reaction to ear drops? Does this look like ring worm? How could she catch it? any advice? 

Hello!  I have seen ringworm looking a bit like this (it usually isn't itchy);  I have also seen skin (bacterial) infections looking like this.  But, regarding the bacterial infection, there are bacteria living on the skin surface and down ears all the time - it only tends to become an 'infection' if the bacteria invade the surface cells for some reason, e,g. the dog is scratching (and disrupts the skins' surface, allowing penetration by bacteria) such as in allergy, or if their immune system is struggling for some reason.  Therefore, a 'bacterial skin infection' is seldom the full story.  The same is true of Ringworm;  I'd associate it with the very young or the immunocompromised, so if it is Ringworm I wonder if there is something underlying it.   There also appears to be hair-loss, which makes me wonder about endocrine diseases such as Cushings.  In extremis, skin tumours can take on all manner of appearances but are comparatively rare.  This has the appearance of comodones - which tend to occur secondarily to other things - but your vet will be able to look properly in the consultation.  Indeed, it sounds as though a visit to your vet for a full, in-context examination is needed in order to take this case forward.  It may prove to the kind of case that is not solved in a single visit.