There are several things that you should do when your Chihuahua has fleas.
The fleas must be removed from your Chihuahua with a special flea comb. This can be done while you have your dog in the bath (or sink). You will comb through his or her coat, the fleas will drop down into the water and be rinsed away. Be sure to cover every single area of the dog. It is a good idea to do this process 2 or 3 times in a row; if even 1 flea is missed your problem will begin all over again.
You must also wash everything that you can. This will include not only your Chihuahua's belongings, but everything in the home. If not, the fleas will just remain on your bedding, couch and carpet and wait for you or your dog to come by.
Wash all sheets, blankets, pillow cases, pillows, clothes, small rugs, dog bed cushions and anything else that will fit in your washing machine with hot water when at all possible. You may also choose to hand wash some items in the bathtub using warm water and a lot of soap.
3) As the items are being washed and you have de-fleaed your Chihuahua you should keep your dog somewhere safe until you are done cleaning the home so that he is not exposed to them. Be careful that while transporting your dog that you do not pass any area in which a flea can jump on him. While he is flea-free you can then continue washing the items and then the vacuuming must begin.