One of mine gets it. He seems to have quite sensitive everything including skin but half his chin is white. I noticed he had a massive scab and another smaller sore along his gumline. He had it quite bad when I realised what it was. I initially thought it was a scab from fighting. Anyway, I switched bowls to stainless steel. The plastic ones get germs in them easily in any smal scratches, and he's a very messy eater. They were also quite high sided bowls so would easily touch his chin. Also made sure bowls were washed in anti bacterial washing up liquid.

I took him to the vet and the vet gave him antibiotic injection and anti inflammatory. Being the sensitive soul he is he reacted to these jabs and pee'd out his butt for a few days until I got some other stuff to settle him down.

It is pretty much the same way some people are prone to acne, and you just need to keep an eye on it and if needbe clean the chin with hibbi scrub. He's losing a bit of hair under his chin at the moment and I think I saw a small spot forming so I am going to make sure I order some today. I believe some people have even sworn by facial cleansing wipes from the likes of Olay.