It is usually an indication that the animal had a fever a few days ago. Usually by the time they are peeling, you have either treated them, or they are over whatever caused the fever. Chances are that the animals whose noses are peeling won't have a fever now. Or, possibly photosensitivity, although if that is the problem, they should be peeling anywhere there is white markings.
The other option could be sun or wind burn, but I can't say that I have ever noticed much of that.