I. Overview This disease is called white acne or white moss of milia. It is a benign swelling or retention cyst originating from the epidermis or epithelium of the appendages. It can occur at any age and gender, and is also seen in newborns. Post-traumatic papules often occur after abrasions, scratching or inflammatory facial eruptions. It is common in the damage of epidermolysis bullosa or herpetic epidermolysis bullosa, and can also occur after herpes zoster blisters. Some patients have genetic factors. Diagnostic points (a) The history of the disease is slow and can last for several years, and finally the scar is formed by natural shedding. (B) Clinical manifestations and typing A. Symptoms 1. The damage is creamy white or yellow, pinhead to rice-sized solid papules with rounded tops, covered with very thin epidermis. 2, secondary damage is mostly distributed around the original lesions, can last for several years, natural shedding, no scar formation. 3, individual damage can have calcium salt deposits, as hard as cartilage, dark yellow when the damage increases. 4, most commonly seen on the face, especially the eyelids, cheeks and forehead. Adults can also occur on the genitalia, and infants are usually limited to the eyelids and temporal region. B. Signs: White corn-like papules are the special signs of the disease. (C) Clinical typing 1. Primary type: It begins in newborns and is formed by the undeveloped sebaceous glands, and the damage may disappear naturally. 2.Secondary type: It often appears after inflammation and may be related to damaged sweat ducts. It can develop after sun exposure, after second-degree burns, after herpetic epidermolysis bullosa, after delayed cutaneous exoporphyria, after herpetic lichen planus, after herpes-like dermatitis, after aspergillosis, after aspergillosis-like and after X-ray irradiation. Histopathological diagnosis shows an epidermal cyst with a wall composed of multiple layers of flat epithelial cells and a cavity filled by keratinocytes arranged in concentric circles. Treatment This disease is benign lesion, usually no conscious symptoms, usually do not need treatment. Local treatment: disinfect with 75% alcohol, pick the skin on the surface of the papule with a needle, and then pick out the white particles.