Irritations of your scalp, if they are caused by a minor injury, can be harmless and clear up on their own. There are, however a number of medical conditions, which can cause scalp irritations. Psoriasis and contact dermatitis but also infected injuries are common causes for itchy and irritated scalps. It feels very uncomfortable and needs to be treated.
You should only use a mild shampoo to avoid additional inflammation. Combinations of Oatmeal with medicinal herbs and essential oils with antimicrobial properties can be very effective. A herbal conditioner and/or a herbal rinse based on Vinegar, used every second wash will help to calm and soothe the scalp.