Mole mainly belongs to the skin proliferation disease caused by the aggregation of subcutaneous pigment cells into nevus cells, and usually the itchy nevus area is mainly caused by allergy, infection or malignant lesion: 1.Allergy: If the nevus patient is allergic or contact with allergens, such as eating allergic food, drugs or directly inhaling irritating chemical substances, it may lead to allergy at the nevus area, and then the itchy nevus may occur. 2. Infection: If the nevus is squeezed and stimulated for a long time due to external force or other reasons, it may cause damage to the skin in this area, which may lead to bacterial infection or inflammation, and the patient can relieve the itchy skin through external application or oral anti-inflammatory drugs; 3. Malignant lesion: If the nevus remains unchanged for a long time but suddenly appears itchy, the patient should be alert to the possibility of nevus mutation. However, if a nevus with a diameter of >1.5cm and accompanied by itching, erosion, pain, crusting and rupture, patients need to go to hospital for relevant examinations, such as dermoscopy, in order to prevent the nevus from mutating and producing melanoma, and if not detected and treated in time, cancer cells can grow into the bones of patients or metastasize to lymph, brain and lung, which can threaten life in serious cases. If a patient has an itchy nevus, it is recommended to observe the skin condition first, and if the itch is serious, it is recommended to seek medical treatment in time, and if it is diagnosed as a nevus tumor, it should be treated by surgery in time to remove the lesion to avoid affecting the body.