bumps on ears(photos)

Hello,

One of my cats has some red bumps on her ears.  I noticed it last week and took her to the vet, they said it looked like bug bites and wasn't showing any signs of infection so they gave her some advantage and we went home.  It's a week later, the bumps look worse.  They've swollen and there may be more than before or either they were there and since they've swollen, they've just become noticeable. Two weeks ago, I adopted another cat and he had ear mites.  I don't think ear mites could cause bumps like this on the outer ear, but I'm not sure.  I gave them both advantage so the ear mites should be gone anyway.  It may be an allergic reaction, but besides the other cat, I haven't gotten anything new.  I've attached some pictures below.  Any advice on what this may be, or tips on how to treat something like this would be very appreciated.  Thank You.

I would have to see a better photo, but an allergic reaction to a bug bite seems possible.
 

I think it looks like some sort of bite and allergic reaction. Does she scratch her ears alot? Could it be irritation from overscratching?

Thanks for your replies.  She has been scratching a lot, I think that's why it's become swollen.  Hopefully it's just an allergic reaction, I couldn't get a better picture cause she wouldn't hold still.  I'll be monitoring it closely.  I wonder if there's anything I can put on it for itching though.
 

Program has helped me with 'bites' around the ears which are usually related to flea dermititus. It could also be flies, fleas, mossies, reaction to buffalo grass, etc. You could try some insect repellant if it's flies etc. Keep an eye on her and work out if there has been any changes in the environment - ie different food, different washing powder used for her bedding or something changed in the house?

I have counted out fleas, my 2 cats sleep next to each other often, and the other one has no fleas and I couldn't find any. S.N.E.A.K. IS 2.5 years old and she's in her 3rd spring soon so allergies are not a problem either! She's an indoor cat and I change litter brands, food brands, often and it has never been a problem before. As for insect repellent, I wouldn't feel right about putting something on my cat that has a chemical base to it. I try to feed them healthy food such as raw moose, fresh codfish and trout and other food from the ocean and woods. I'm lucky in this way because living in NFLD allows me fairly easy acess to things!!