This is most likely a staph infection that he is picking up from his surroundings. He could be getting it from the vicinity where he sleeps. Either outside on the ground or it can be from some kind of irritant in your carpet or floor cleaner.
There can be anal sac problem, which can be treated by antiseptics and antibiotics. Some times it becomes necessary to remove them surgically, which does not create any complication. There is also a chance of tumor, which has created sores all over its private parts. If the tumor is not anal sac tumor but perianal adenoma or some other tumor then it is not necessary to remove it through surgery. Take it to vet to get exact diagnose in order to start its treatment soon.
The only other thing you might do is washing his belly area with an antibacterial soap each day but make sure you dry the area carefully. Put something like Gold Bond powder on the area. All or none of this may help.
It could be a simple as his immune system letting him down at his age.
There can be anal sac problem, which can be treated by antiseptics and antibiotics. Some times it becomes necessary to remove them surgically, which does not create any complication. There is also a chance of tumor, which has created sores all over its private parts. If the tumor is not anal sac tumor but perianal adenoma or some other tumor then it is not necessary to remove it through surgery. Take it to vet to get exact diagnose in order to start its treatment soon.
The only other thing you might do is washing his belly area with an antibacterial soap each day but make sure you dry the area carefully. Put something like Gold Bond powder on the area. All or none of this may help.
It could be a simple as his immune system letting him down at his age.
