The examination items of pemphigus include questioning, hair pulling test, microscopic examination, dermoscopic examination and so on. 1. Questioning: The doctor will ask the patient about the time when the hair loss appeared, ask about the family history of hair loss, and ask whether there are other diseases such as vitiligo. 2. Hair pulling test: the patient does not wash his hair for five days, after which he pulls up a bunch of hair and pulls it in the direction of the tips to observe whether there is any hair loss and how many hairs fall out. 3. Microscopic examination: It is necessary to pull out a hair at the edge of the hair loss area, and observe the lower end of the hair with a microscope to see if there is any atrophy phenomenon such as thicker at the top and thinner at the bottom. 4. Dermatoscopic examination: use the dermatoscope to observe the area of hair loss, whether there are yellow spot signs, dystrophic hair, black spot signs and other phenomena. If patients find abnormal hair loss, they should consult a doctor in time to get a clear diagnosis and standardize the treatment according to the doctor’s instructions.