Patients with itchy scalp may be related to factors such as not washing hair for a long time, fungal infections, seborrheic dermatitis and allergic skin diseases. 1. Long time not washing hair: If patients do not pay attention to personal hygiene and do not wash their hair for a long time, it may lead to the accumulation of scalp oil, dandruff, and dirt, which can lead to cause scalp itching. 2. Fungal infection: when the patient’s scalp area is infected by fungi, triggering inflammation, red spots, pimples, blisters and flakes may appear on the scalp area, accompanied by obvious itchiness. 3. Seborrheic dermatitis: seborrheic dermatitis is a common chronic superficial, inflammatory skin disease, the scalp area may appear erythema on the basis of scales, can be accompanied by itching, patients with itchy scalp may be caused by seborrheic dermatitis. 4. Allergic dermatosis: when the patient frequently permed and dyed or use irritating shampoo triggered allergic dermatosis, the scalp area may appear erythema, pimples, blisters and other lesions, accompanied by itching, tingling, redness and swelling and other symptoms. It is recommended that patients seek timely medical examination to identify the cause of the disease and then targeted treatment, pay attention to scalp care in life, avoid scratching the affected area with violence to avoid infection, and at the same time do a good job of monitoring the condition of any abnormalities in a timely manner to seek medical attention.