The worst-case scenario for itchy scalp is a condition that results in hair loss.
Ringworm is often marked by round patches of broken-off hair, but if there are no complications, it will grow back. In some instances, ringworm can result in a painful bump with a thick yellow crust, known as a kerion. These can cause scarring and permanent hair loss, but they are rarely found in kids older than 10.
Psoriasis-related hair loss, which is usually temporary, can happen if there's too much scratching or if scales are removed too vigorously. Gentle treatment is best when it comes to the product and how it's used.