Itchy hair that touches the chin and small blisters may be caused by contact dermatitis. Contact dermatitis can result if the patient is allergic to shampoo or has used chemicals such as hair dyes. Contact dermatitis is a skin allergy that occurs when a person reacts to a substance he or she has been exposed to. In the acute stage, there will be localized redness, itching, pimples, and in severe cases, blisters and oozing, or even erosion. In the chronic stage, localized dryness and flaking may occur. Patients are advised to change a kind of shampoo or tie up their hair to avoid touching the chin as much as possible, meanwhile, choose some anti-allergic drugs under the guidance of doctors, such as loratadine, cetirizine hydrochloride tablets and so on. If the symptoms can not be relieved, it is recommended to go to the hospital in time, to clarify the cause of the disease after treatment.