Purple blood pus behind the ear, this condition may be an abscess caused by trauma or sebaceous cysts and folliculitis infection. In this case, the first step is to use sensitive antimicrobial drugs for treatment. This condition is caused by infection with gram-positive bacteria such as Staphylococcus aureus or hemolytic streptococcus. First-generation cephalosporins, macrolides, and penicillins are chosen for treatment, and commonly used oral medications include cefadroxil, roxithromycin, and amoxicillin clavulanate potassium. In severe cases, intravenous medications may be given if systemic symptoms such as fever and headache are present. Locally, puncture and drainage or incision of the abscess can be considered. After incision of the abscess, the necrotic tissue should be removed, and the abscess should be washed out repeatedly with hydrogen peroxide, povidone-iodine, and saline. If the granulation tissue is relatively fresh, you can also consider applying Bevacid and high sugar solution, spraying or rinsing to promote the growth of fresh granulation tissue, and in severe cases, you can also consider the second stage of debridement and suturing.