Melanosis is a disease in which the skin turns from brown to black. It is similar to the “sallow spots” described in Chinese medicine. It is characterized by an initial flushing, self-induced tingling and itching, which is aggravated by sunlight, and is usually found in light brown, dark brown, or gray-black pigmented spots on the face. It is thought to be a variation of photosensitivity dermatitis or phototoxic dermatitis. The etiology of this disease has not yet been clarified. The Chinese medical literature often puts this disease and chloasma together, and the Qing dynasty’s “Jinjian of Medicine. The Essentials of the Surgical Heart Method. Sallow epidermis” said: “This evidence is a sallow spot. The initial color is like dust and dirt, and over time black like coal-shaped. Withered darkness is not lustrous, the size varies. The small ones are like corn grains of red beans, and the large ones are like lotus seeds and gorgonians. Or long or oblique or round, in the skin flat.” 1, etiology and pathogenesis 1, liver depression and blood deficiency liver depression, blood deficiency can not nourish the skin, sunlight exposure, but the poison of cosmetics, so that the fire poison stagnation in the internal and become. 2, kidney deficiency blood deficiency diet is not regulated, the spleen and stomach inactive, kidney deficiency blood deficiency can not nourish the skin and become. Diagnostic points Prevalent in adults, more common in women. The lesions can be found on the skin of the whole body, mainly involving the face and neck, upper limbs and other parts. The course of the disease is slow, mostly stopping after a few months, and the pigmentation exists for a long time, but a few can fade on their own. Initially, the lesions are erythematous or light brown spots, but later they gradually expand to become dark brown or greenish gray diffuse patches, sometimes accompanied by mild itching. It may be accompanied by general symptoms such as dizziness, fatigue, poor appetite and emaciation. It can also be seen on the chest, hands and forehead. In addition to hyperpigmentation, limited capillary dilation, follicular keratotic papules and a little fine flaking can be seen, resulting in a leaden gray face. The disease does not involve mucous membranes. The disease mainly involves the face, mostly from the two temporal areas, gradually spread to the forehead, cheeks, before and after the ears, and expand the entire face, and can even involve the neck side of the forearm, axillae, umbilicus and other parts of the body. However, the perioral area and chin are often not invaded, and the mucous membranes are not involved. The lesions are reticulopigmented, initially flushed, and gradually deepen in pigmentation from yellowish brown to light black. Around the hair follicles, diffuse patches slowly form, but the pigmentation is lighter in the center of the face and anterior aspect of the neck. It is often accompanied by mild reticulo-capillary dilatation, and in the neck there are often chaffy flakes. The appearance is like a layer of white powder, and the boundary is not distinct from normal skin. 2, tar melanosis mainly seen in long-term exposure to coal tar, asphalt and its fumes, distributed in the face, neck and forearms and other exposed parts, and the periorbital, zygomatic for the most obvious. The lesions are initially erythematous, edematous and may have scales on them, and follicular papules and blackheads may be seen, showing characteristic acne-like changes. Later, the color gradually deepens, light brown to dark brown, with diffuse or reticulated pigmentation, often accompanied by capillary dilation, mossy papules, and follicular keratosis. It is often aggravated after sun exposure. 3, post-inflammatory melanosis It is a kind of skin pigmentation secondary to acute and chronic inflammation. It generally occurs sooner after dermatitis, and the pigmentation spots vary from light brown, purple-brown to dark brown. It is confined to the inflamed area of the skin and is slow to fade, often lasting several months. The pigmentation further deepens after sun exposure or re-inflammation, and even mild mossiness occurs, which lasts for several years. It is usually easy to cause different degrees of hyperpigmentation after lichen planus, pityriasis rosea, herpes zoster, lupus erythematosus, fixed drug rash, herpes-like dermatitis, neurodermatitis, insect bite dermatitis, pyoderma, etc.