Hello and welcome to the forum. Thanks for your post. Ketocanazole shampoo is for fungal issues of the scalp. https://www.healthline.com/health/ketoconazole-shampoos While it helps many people that have flaking of the scalp, it also can cause skin irritation for some. Did a doctor recommend it? A dermatologist is good to talk to about issues related to one's scalp and direction on how to treat it. You may be allergic to ketocanazole shampoo as severe itching is a sign of that. A lot of times, a tar based shampoo can be effective for dandruff. Here's a guide that goes through options. https://www.mayoclinic.org/diseases-conditions/dandruff/diagnosis-treatment/drc-20353854 But your best bet at this point is to speak to a dermatologist.