We experienced a similar problem a few years ago. We found that the dog was bringing wood ticks in and they had fallen off and were hatching in the carpet and woodwork. This had us, especially myself, quit upset as I hate the things. The solution was to vacumn often and spray with bug killer. We eventually wiped them out with no further problems. Sounds like the same thing may be happening to you. We are in Tucson, where you would not think there were ticks in the desert.