Mycosis fungoides cannot be diagnosed in the early stage, mainly because of atypical symptoms, early blood tests cannot find abnormalities, and biopsies need to be performed several times before specific lesions can be found. 1. Atypical symptoms: the course of mycosis fungoides is a kind of chronic progressive process, from the early stage to the tumor stage may be up to several years or even decades, in the early stage of the symptoms are not particularly typical, mainly there will be some erythema, and some other skin diseases are more similar to the more difficult to find. 2. Blood test: the diagnosis of mycosis fungoides requires blood test, but in the early stage of the disease, the blood test can not find any abnormality, only in the late stage of the disease, there will be mild anemia or hemolytic anemia, and there will be an increase in the number of white blood cells and so on. 3. Biopsy: Mycosis fungoides needs to be diagnosed by biopsy. It is not easy to find specific lesions in early biopsy, and even in late stage, it needs consecutive slices to find specific lesions. If mycosis fungoides is suspected, it should be reviewed on a regular basis, clinical symptoms should be observed and medical attention should be sought in a timely manner, and once diagnosed it should be treated aggressively to improve the quality of life.