Fatty granules generally refer to cornus rash, including primary and secondary cornus rash. Primary cornus rash may be related to genetic factors, and secondary cornus rash is caused by herpetic disease, trauma, and so on. 1. Primary cornus: some patients have family history, which may be related to genetic factors. It can occur on its own and there is no clear pathogenic factor. 2. Secondary milia: It can be secondary to herpetic diseases such as herpetic epidermolysis bullosa, porphyria cutanea, etc. Or secondary to trauma, it can be secondary to herpetic diseases and trauma. Or secondary to trauma, can occur after skin abrasion, can also occur after the facial rash or scratching, abrasion. If the patient wants to deal with the cornu rashes, he should go to the hospital in time, and regulate the treatment under the guidance of the doctor.