A hard bump on the cartilage of the auricle may be caused by auricular pseudocysts, sebaceous cysts, folliculitis or boils. 1. Auricular pseudocyst: it is a cyst-like bulge on the outer side of the auricle, containing plasma exudate, mainly due to some mechanical stimulation. When the fluid is absorbed and mechanized, a hard mass can be formed. 2. Sebaceous cysts: the sebaceous glands of the auricle are blocked by secretions, and sebum gathers into cysts, thus leading to sebaceous gland cysts, which are common in the head and face. 3. Folliculitis or boils: usually due to trauma or other causes of hair follicle damage, bacteria invade the hair follicle, forming a limited infection. The most common bacteria that cause folliculitis are Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus b hemolyticus. Long-term use of hormones and diabetes are also prone to trigger folliculitis. It is recommended that patients go to the hospital, under the guidance of the doctor for treatment, do not use drugs without authorization, so as to avoid adverse consequences.