Itchy hairs may be caused by fungal infections, folliculitis, seborrheic dermatitis and other reasons. 1. Fungal infection: itchy hair thick place, may be localized fungal infection, caused by ringworm and other diseases, may also be accompanied by scalp erythema, dandruff, hair breakage and other changes. 2. Folliculitis: the hair follicles in the thick hair distribution is exuberant, easy to secondary bacterial infection such as Staphylococcus aureus, causing folliculitis. It may lead to itching and pain in the thick hair area. 3. Seborrheic dermatitis: the etiology is unknown, it may be related to the colonization of Malassezia bacteria, as well as the increase of oily secretion of hair follicles, immune factors, impaired barrier function of the skin, which may also cause itching of the scalp. There may be other reasons for itching in thick hair, and you should go to the hospital in time for examination and treatment as prescribed by the doctor.