It is common to develop skin issues after having had fleas. Cats can develop an allergy to flea saliva and also acquire tapeworms from the fleas. If you have not already, bring a stool sample to your veterinarian to check if your cat needs to be wormed for tapeworms.
DERMA-IONX is safe and can help with the allergy response. I prefer to add 10 drops to the food at breakfast and supper. Once improvement is seen you can give 20 drops once a day on one of the meals. I would also give PROBIOTICS and OMEGA 3,6,9 to restore the gut and reduce inflammation.
You should also check your cat daily with a fine tooth flea comb checking for fleas or flea debris until the problem is resolved. Only one flea bite can get the allergy response started.
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