This was the best explanation I could come across from one of our own members...
"Mouth rot or otherwise called stomatitis is basically caused by an absess in the mouth from an injury to the mouth, gums, or both. It is also caused by improper temperatures as well, which will depress the immune system. If they are kept at improper temps they cannot digest their foods very well & can also develop GI distress. GI infections can manifest into mouth rot as well or a mouth infection. Those are all secondary problems. Mouth rot will look like a pus pocket or some describe it as cottage cheese like looking substance in the mouth.
Other problems like toe rot or tail rot or necrosis can be caused by tail nips, toe nips, injuries to that area, or retained shed. If the circulation is cut off to those extremities they can lose them. If they suffer from a tail or toe nip, they can become infected & lose them.
Problems such as these normally need to be treated with an antibiotic.
I hope this helps out some. Let me know if you need more information.
Tracie"