gave her Flea topical a little early when she first started to seem itchy. I've not seen any signs of fleas, but she has always been very reactive to their bites,
what product are you using? many of these products seem to be losing their effectiveness. You might need to switch to one of the oral medications.
A flea-allergic dog can scratch themselves raw from fleas even if there are so few fleas you don't even notice them.