Get Your Dog Care Questions Answered by Experts
Hi, I'm a licensed veterinarian and I'll be happy to help.
Your initial suspicion, is probably correct -- This sounds like a classic case of Flea Allergic Dermatitis. Just like when we get bitten by a mosquito, the itching continues long after the bite is over. Flea bites remain itchy for many days or weeks beyond the bite.
So, the usual treatment is cortisone. Typically by injection or pills, but sometimes a topical cream may be useful. You can apply 1% hydrocortisone cream over the affected areas, but I would recommend seeing a veterinarian if there's no improvement within 24 hours.
In cases where excessive scratching has led to infection, antibiotics are also necessary.