I have a rotti that is about two years old, just today I noticed that he has a swollen nose and it is bleeding and he keeps scratching it which is making t worse. My boyfriend thinks it may be ant bites because he is an outside dog and sometimes spills his food all over which would attract ants. Is there a sure way for me to tell which it could be?

Speaking from a laymans point of view I would agree with your b.f that it is not mange. I was raised in the country and saw countless strays with mange and can't ever recall seeing it only on their nose.

If the nose is still swelling or hasn't gone down by tomorrow, call the vet (call ER vet tonight if any difficulty breathing). A bite or sting sounds likely, since it came up so fast.

My parents have a dog who suffers from allergies. Certain times of the year he scratches enough to lose patches of hair and bleed. I believe that they give him a small dose of benadryl and it relieves the symptoms. I wouldn't recommend trying that unless your vet reccomends it, but its something to keep in mind...

Probably is an insect bite of some sort. I would keep and eye on it and if his condition worsens or does not improve within 3 days, I would call the vet. He may be licking it more now that it is bothering him which will cause it to become raw. Antibacterial ointment such as panalog can help.