Dandruff and itchy head may be caused by physiological factors such as inadequate cleaning, or it may be caused by seborrheic dermatitis, ringworm of the head and other diseases. 1. Physiological factors: if people do not wash their heads for a long time, it may lead to the accumulation of oil on the head and the phenomenon of increased dandruff, which may also be accompanied by an itchy feeling. 2. Seborrheic dermatitis: this disease may be related to heredity, Malassezia infection, neurological dysfunction and other factors, the triggers include fatigue, mental stress, etc. When it appears on the head, it will produce a large amount of grayish-white dandruff, and there will also be itchy symptoms. 3. Ringworm of the head: ringworm of the head is caused by dermatophyte infection, can be infected through direct contact, indirect contact and other ways. At the beginning of the disease, there will be red papules, and then the surface of the lesions is covered with grayish-white scales, which is manifested as increased dandruff, and the patients are conscious of itching. Dandruff itchy head in the exclusion of physiological factors, it is recommended that the patient to the hospital examination, follow the doctor’s instructions for treatment.