Intradermal nevus is a benign skin tumor formed by proliferation of melanocytes. The growing size of intradermal nevus may be a normal phenomenon, or it may be caused by undesirable stimuli. The cause of intradermal nevus has not been fully clarified, and it is considered to be related to heredity, living habits, and prolonged exposure to sunlight, etc. Patients with intradermal nevus usually have no conscious symptoms. Patients with intradermal nevus usually have no conscious symptoms, and the lesions may appear as hemispherical elevations, brown or normal-skinned papules or nodules. 1. Normal phenomenon: intradermal nevus can be found in children, with age, intradermal nevus may also increase gradually, which is a normal physiological phenomenon, it is recommended to observe closely, do not often cause stimulation to the local area. 2. Unhealthy stimulation: Nevus of skin is a benign growth, the chance of malignant change is relatively small. However, frequent friction and stimulation from outside may lead to infection and malignant change, and the nevus may gradually become bigger. If the intradermal nevus has black damage, increased or uneven melanin, itching, burning pain, high lesions and enlargement, it is recommended to go to the dermatology department of the hospital, and if necessary, carry out pathological biopsy to clarify the cause, and also cooperate with the doctor’s treatment.