Ask a Dog Vet and Get Answers to Your Dog Veterinary Questions
If you are unable to get to a vet for flea preventative, you can pick up a product that is over the counter. The most effective one, is Frontline. It's available at most pet stores, as well as some online sources. You can use that every 3-4 weeks as a topical preventative.
For the itching, you can also use Benadryl. The dose in dogs is 1-2 mg per lb body weight. It can be given up to every 6 hours.
I hope this helps, let me know if you have any other questions.