I recently took my white Persian cat to the vet. Her normal skin color is pale pink. In the past year there have been black splothy areas that are some form of dander being produced from inside the hair shaft. The vet recommended medicated shampoo -- bathing 2x/week for 3 weeks. Then once a week -- for total of 2 months. No improvement or decrease in the black splotchy areas. The black dander resembles what you would think is flea dirt -- but it's not from fleas.
The other proposal was to change to prescription diet food as he indicated it could be possibly caused by food.
As he examined the skin there was no discharge, and he ruled out the possibility of ring worm or viral issue.
Has anyone experienced this with their cat? How did you resolve?