Freckles has a rash on his snout

[LabDad]

Took Freckles to the Vet Monday to have this rash examined. The Vet did several test that were negative for mange and a common fungus. I ended up with a prescription for Maleseb Pladgets, medicated pads that I rub on the rash twice a day.
I think he picked up this fungus by rubbung his face on the ground which he commonly does before rolling on his back in whatever wonderful smell he has located..
Anyone have any experience with this medication. It seems to be working and should have this cleared up in a couple of weeks.
Here is a photo of that rash.
http://home.flash.net/~jdebess/Photos/rash.jpg

[Zoom]

Has the vet ruled out the rash as an allergic reaction?

[LabDad]

Zoom,
That of course is always a possibility but Freckles has been allergy free since we got him over two years ago. Also this rash is very local occurring only on the left side of his mouth as shown. I would think an allergy rash would be more wide spread.
If this medication does not work then it may indeed be an alergic reaction.
I have only been treating the area for about four days and it does seem to showing less redness.

[Zoom]

Not necessarily. I see dogs that have one tiny spot of swelling/redness of their paw, but they have a diagnosed allergy rash.

Allergies do crop up 'out of the blue' occasionally. I've never had allergies in my life until the past two Augusts have shown up...then I'm a sneezing, sniffling wreck until the first frost.

I just wonder about the accuracy of a fungal diganosis, since you said that those tests had come back negative, and I would think it would show up on both sides of his face or a spot on his back.

[bubbatd]

Does her always rub on that side ...or both ??? Could it be something on the carpet ??