Baldness on and behind the ear

Has anyone come across this before? My 1.5 yr old male gwp has a bad attack of fleas in oct/nov and began to lose hair behind the ears. Treated with over the counter, then braveco. Fleas gone. Since then the baldness has spread to the side of the ears and is the same both sides. Doesn’t bother Reuben at all. No scabs, redness, not sore or itchy. Has a chicken free diet due to repeated issues with malesesia which have resolved. Vets haven’t seen this before & want to see if the hair regrows after the shedding cycle. I’m not convinced this will happen. Hoping someone may have experienced this before. We have also used benzyl benzoate & deosect on the outer ear Incase of mites. Help!

Hello - Aw, Reuben does look slightly dishevelled there.  Hair loss caused by fleas is often quite distinctive because the hairs are broken mid-shaft, ditto hair loss from scratching d/t ear disease or allergies. My understanding is that hair-loss due to yeast infection looks similar, but with yeasty skin.   Your vets will by now know what point in the hair cycle they are worried about, which will probably suggest a group of causes. One of my favourite causes to find is a mite called demodex.  It doesn't itch or even crawl much and is invisible to the naked eye. Most dogs have a few demodex knocking about in their hair follicles (kept in check by the dogs' immune system), but at times of mild social or physiological stress, the immune system can drop, so the demodex can multiply and patches of hair can noticably fall out.  This is quite common - I would have expected your vet to have seen that before and there are tests (scrapes) they can do for it. Ringworm causes hair loss.  If this is likely, your vet may test and give you advice regarding keeping yourself and others safe. Another group of diseases causing hair loss are the endocrine (hormal) diseases, including Cushings or hypothyroidism.  These are often acvomoanied by other signs of these diseases such as lethargy, but I have found that dogs don't always read the text book in this regard and sometimes coat changes are seen first. This isn't a comprehensive list - lymphoma may present in odd ways sometimes and I'm sure that there are others.  However, those are more likely / frequent culprits. Please will you let me know what is eventually found?