Hair loss, lesions, and itchy on Alethea

Hey everyone. 3 weeks ago, I took Alethea to see the vet because there was hair loss and a tiny bit of scabbing on the side of her face. The vet gave me a small tube of medication (Seborrhea Spot-on) to apply each day, and said come back if there's no improvement. 

A week later, the bald spot had doubled in size, so back to the clinic we went. The vet sent away samples for a fungal culture and skin scraping test. 

The results just came in, and they're both negative. So the cause is definitely not ring worm, mites, etc. 

At this point, the vet really isn't sure what's wrong, so I'm wondering if any of you have seen something like what's in the photo.

We're all ears! Thanks, 

Nick & Alethea

Sorry Alethena isn't feeling well.  Have you changed her food in any way?  Litter?  Any new cleansers? 

Is she scratching?  I'm thinking an allergy to something.

Hi Ritz. Alethea scratches the area a few times day. Her food and litter have stayed the same for the past 6+ months, and we haven't used any new cleaners in the house recently. If it's an allergic reaction to something, how can we figure out what she's allergic to?

Allergies develop over time, so it could be something she has not had a problem with in the past. Depending on what you are feeding her (like any dry), I would try a novel protein limited ingredient diet. Something with no grains, starches, fruits or veggies.