Hi there! Well your post states that 'my chi is allergic to fleas'. If that is the case, get rid of the fleas. Use the vet prescribed pill that kills fleas in 30 minutes, then use a flea product to use on him. Then you have to treat the house. Vacuum, vacuum like mad. Get the floor boards, corners too. Then every day use a flea comb on him, to get any fleas he may have picked up. Depending on where you live, this can be a year round problem.
I had ticks in my 100 year old house, and it took me 3 years of exterminators to get rid of them. They hid in the floor boards etc. Then the 'warranty' would not be in effect. Finally I called them after 28 days and told them I saw a tick, and they came back for no charge and treated the house again. That got rid of the eggs. I'm NOT saying that its going to take you 3 years---these were ticks, not fleas. Good luck.