Freckles are an autosomal dominant disorder, and the onset of most freckles is determined before birth (genetically determined). The symptoms are tiny yellowish-brown spots on the face (the size of a grain of rice, not fused with each other), which develop during school age, become obvious during puberty, and turn inconspicuous in middle age. It is more common in women and the symptoms worsen during pregnancy, so it may be related to female hormones. The skin of patients is mostly fair and dry. Freckles tend to be scattered on the cheeks, lower eyelids, and the root of the nose, while some patients involve the upper eyelids, forehead, nose, perioral area, or even widely distributed over the whole body. Sunlight can aggravate the symptoms of freckles, so freckles are more obvious in summer, and freckle patients should use sunscreen in summer and on strong sunny days. The pigmentation of freckles is located in the epidermis, and its pathological manifestation is the increase of melanin in the basal layer of the epidermis, while the number of melanocytes does not increase significantly. Currently, the more effective treatments for freckles are intense pulsed light (photon) and Q-switched laser. Photon treatment does not break the skin, so there is no need for post-treatment leave, and because of the large treatment head, the entire face can be treated without missing a beat. Q-switched laser (commonly used 532nm, 755nm, 694nm) is also very effective for freckle treatment, usually only 1-2 treatments are needed to achieve complete elimination, but the disadvantage is that the treatment will damage the epidermis, requiring a few days of rest and recovery time. In addition, for the very small and unidentifiable freckle lesions, the treatment cannot be done one by one. It is worth noting that most freckles will recur to varying degrees after treatment, and it is still difficult to find a cure with long-term effects.