Home and Garden What causes an excessively itchy scalp? What causes an excessively itchy scalp? Dandruff and seborrheic dermatitis These are the most common reasons for an itchy scalp. “Your body's inflammatory response to an overgrowth of yeast causes the itching and flaking associated with these conditions.Feb 5, 2020 How do I get my scalp to stop itching? - Apple cider vinegar. - Organic coconut oil. - Peppermint oil. - Meditation. - Tea tree oil. - Zinc pyrithione shampoo. - Salicylic acid. - Ketoconazole shampoo.