infestation on my rat

Question
Recently on one of my rats, i have noticed him constantly scratching under his chin and around his shoulders.  He is scratching so hard hes bleeding and scabbing like crazy.  I have done some research and I think he has some sort of infestation, even though I cant see any when looking through his fur, I still highly think he has it.  

He is loosing his fur, and i notice tan patches on his skin if it means anything.

Does he have an infestation? if so, how can I tell what kind it is? ex. Lice, mites .. and what should i do? im really worried.

thanks, Amber

Answer
Sounds like lice or mites (generally you can see lice, so I'm going to say it's mites). You need to either go buy some ivermectrin from your local horse feed store (it comes in a paste form) and give him the equivalent of a grain of rice once every two weeks for two dosages; or you need to get in to a vet so they can get ya on some anti-parasticals.

Good luck!