Rare Reasons For Continuing Itchy Scalp. Seborrheic dermatitis is a condition of excess dandruff on the scalp due to an overreaction to yeast that lives on the skin. It can be caused by a number of factors and can be a symptom of an underlying medical condition.
Or it may be associated with: Itching can be caused by a number of different conditions, including: Sores or scabs on the scalp are often harmless and clear up on their own.