Moles that slowly get bigger with age may be caused by age, external stimuli, change in nature, etc. For specific cases, it is necessary to go to the hospital to find out the cause of the disease. 1. Ageing: As we age, moles will grow in proportion to the increase in body surface area, which is a normal phenomenon. 2. External stimulation: When localized by external stimulation, such as ultraviolet radiation, people’s skin color will become darker, and the pigmented nevus will become darker and bigger accordingly. At the same time, if the mole is often rubbed and scratched in daily life, the mole will gradually become bigger because of this mechanical stimulation. 3. Change of nature: If the mole of the patient becomes bigger rapidly in a short time, the boundary of the mole is not clear, satellite foci appear around it, the color is not uniform, and accompanied by pain, bleeding and other symptoms, the mole may have malignant changes. When the mole of the patient becomes bigger gradually, it is recommended that the patient should go to the regular hospital in time, and the cause of the disease should be clarified and targeted treatment should be carried out under the guidance of specialized doctors.