The secretion of preauricular fistula comes from the hair follicles, sweat glands and sebaceous glands in the lumen of the canal. The lumen of preauricular fistula is lined with complex flat epithelium with hair follicles, sweat glands, sebaceous glands, etc. Therefore, a small amount of white mucous or cheese-like secretion overflows from the opening of the fistula when it is squeezed. And the complex flat epithelial tissue will be shed, the shedding of the skin tissue accumulation in the lumen, and sweat, oil and grease mixed with bacterial infection can easily occur. Congenital preauricular fistula, a common clinical congenital disease of the outer ear, is the remnant of incomplete fusion of the auricular primordia of the first and second gill arches during development, and is a manifestation of congenital embryonic developmental abnormality. In most cases, the preauricular fistula opens in front of the foot of the auricle and has multiple branches of varying depths, forming multiple blind tubes, and in some cases bypasses the ear to form an infection behind the ear. If an infection occurs, go to the hospital and follow the doctor’s instructions for systematic anti-inflammatory treatment, after the inflammation is under control, surgical excision treatment.