Vivid nevus is a kind of birthmark, also called wine-like nevus or capillary dilation nevus, which often appears at birth or soon after birth, mostly on the head, face and extremities, and sometimes involving mucous membranes. The damage is initially of different sizes or several light red, dark red or purple-red patches, irregular in shape, with clear borders and not higher than the skin surface, and capillary dilation is visible. With age, the color deepens and becomes red and purple, and the lesion will gradually expand in 40% of patients, and can thicken and appear nodules before the age of 40, and bleed easily after trauma. Erythema nodosum is a micro-venous malformation, and the lesion area increases with body growth and does not fade throughout life. Because the lesion reaches deep into the dermis, conventional treatments (such as cryotherapy, high-frequency electricity, ordinary CO2 laser treatment, isotope treatment, etc.) are difficult to get rid of it or tend to leave scars. With the development of laser application technology, the use of selective photothermal action principle to treat nevus becomes a reality, and few hyperplastic scars appear after treatment, and the effect is better for superficial lesions, especially for infantile nevus, so it has become a more popular treatment method. Questions about laser treatment 1. What is the most suitable age for treatment? Since the younger the child is, the stronger the healing ability of the skin is, treatment can be done after the child is born 3-4 months. 2.What are the precautions for laser treatment of nevus of bright redness? These reactions will subside within a week as long as they cooperate with the physician’s treatment (pigmentation may occur in individual patients, which usually disappears on its own within a few months without special treatment). 3.What is the course of laser treatment? Since the lesioned blood vessels are distributed in three dimensions under the skin, each laser treatment can only remove part of the blood vessels, in addition, a small number of vessels will be recanalized after the treatment, so the treatment often needs to be divided into several sessions. The interval between treatments should be more than two months. It takes about one year to treat 4 to 5 times with the laser. 4.What is the effect of laser treatment? About 30% of the patients can be cured and 70% of the patients have greater improvement. Which hospitals can treat nevus of vivid redness? The lasers used to treat nevus are usually pulsed dye laser (wavelength 585/595 nm), long pulse width Nd:YAG laser (wavelength 1064 nm) or variable pulse width frequency doubling Nd:YAG laser (wavelength 532 nm). Patients can choose a reputable hospital with these types of lasers.