bald spot behind ear?

[avasimone]

today i noticed a bald spot behind my cats ear. i work and go to school so i'm not always with him, but i haven't noticed him scratching. there are no scabs, the inside of his ears look the same as ever, and he is not bothered when i touch it. any ideas? should i be concerned? attached are pictures of the affected ear and his other ear for reference

 

[avasimone]

i forgot to add, he was switched to a urinary s/o prescription diet 2/3 months ago for bladder crystals

 

[Mamanyt1953]

If this were an allergic reaction, I'd have expected it to come on sooner...however, any living creature can develop an allergy to any food or medication at any time, so that's not a sure thing. It looks to me as if the skin is intact, and smooth. Is that the case here? No signs of undue scratching?

 

[avasimone]

If this were an allergic reaction, I'd have expected it to come on sooner...however, any living creature can develop an allergy to any food or medication at any time, so that's not a sure thing. It looks to me as if the skin is intact, and smooth. Is that the case here? No signs of undue scratching?

yes, smooth intact skin and i haven't noticed any scratching.

 

[FeebysOwner]

Is it just the lighting, or is that area kind of red? Does that area of his ear feel 'fatter' than the other ear? Not helping to determine what the cause is, but wondering if there is some sort of inflammation within the tissue itself?

I doubt sending a pic to your vet will help much, but it certainly can't hurt.