The redness and itching around the wound three weeks after hip replacement is usually caused by wound scar proliferation, allergy, inflammation, etc. It can be treated and relieved by skin care and medication. 1. Wound scar hyperplasia: In the process of wound healing, the damaged nerves, blood vessels, etc. will naturally grow and repair, and the phenomenon of wound scar hyperplasia is a normal phenomenon. You should pay attention to the cleanliness around the wounds, avoid friction around the wounds, avoid spicy and stimulating foods, and pay attention to more rest. 2. Allergy: due to disinfectant, dressings and other stimulation of the skin allergic reaction, resulting in a red rash around the wound or red and itchy, you should reduce the stimulation of foreign objects, follow the doctor’s instructions to use mometasone furoate cream and other topical application, or take loratadine and other antiallergic drugs to alleviate the symptoms of allergy. 3. Inflammation: Inflammation is caused by wound infection, which can be red, swollen, hot and painful at the incision site, and should be reported to the doctor in time, and local or systemic antibiotic treatment should be given under the doctor’s guidance. If the phenomenon of redness and itching around the wound occurs three weeks after hip replacement surgery, it is recommended that the patient go to the hospital in time for examination and standardized treatment after clarifying the cause of the disease.