Sarcoptes mites

Question
Hi there,

i've got two girlies who were from a rescue but originally from a chain pet store, so there health is awful, in the 2 months ive had them we've had respitory infections abcess's one's got an umbilical hernia and now we have what appears to be sarcoptes mites.
I've been trying to find information on them online but there is some conflicting stuff.
One of the girls started growing a horn type thing on the end of her nose about 2 weeks ago, it was checked out by the vet who said because of respitory issue's she's probably irritated it and just to keep an eye on it which i have. Then a few days ago her sisters ear went all lumpy....i quickly researched it and realised it was almost deffenatly sarcoptes mites so ordered some spot on with ivermectin in it arrived the next morning at which time i'd notice the one with a the horn on her nose also has one tiny lump on her ear so decided to treat both of them.
Neither are itching at all and show no signs on there feet or tails just ears and nose.
My questions basically are:-
should i treat the other 3 cagemates although they show no signs to be on the safe side?
should i pop them to the vets again or continue to treat at home (my vets are usless)?
should i dose them all again in 10tens just to be on the safe side?
And on the websites ive been reading it says that a horn on the nose may appear but only in serious cases of neglect....well i know my girls aren't neglected but why did the horn appear weeks before any other symptoms?
And also where have they picked them up from is it the same as fur mites where they are always there just flare up at certain times?oh and how come there not itching?
any information as soon as possible greatly recieved
thanks very much

Answer

Sarcoptes mites manifest as jagged, irregular shaped,crusty warts on the edges of the ears and nose. It does not spread to any other parts of the body. It stays localized in these areas because they are found mainly in the sebaceous glands of the ears and also in the hair follicles in this area as well.

This condition does NOT cause itching like you would see with other types of mites.  This is known as the "ear mange mite" and to be truthful, it is not a real common thing with our domestic rats. This doesnt mean it cant happen, but its not common.

The good news is, ivermectin is absolutely the way to go.  You can treat all of your rats as long as you know their weight etc...
Did the vet give you the ivermectin?

Also, you refer to the vet as useless, which is not good, but of course, I can relate, believe me, I see and hear this all the time about vets.  So many vets say they see rats and soooooooooo many of them are so clueless they can cause more harm than good.  If you want I can give you some names of vets in your area (once I know where your located) so this way if you need to see a vet that knows what he or she is doing, you will have a place to go.  All rats deserve to have a good vet to take care of their medical needs when the need for it arises.