Skin is a mirror of human health, dandruff flakes fall like snowflakes. Red, itchy and oily skin on the face and back, red spots and flakes on the body …… These seemingly minor skin problems may be symptoms of seborrheic dermatitis. Many people have been bouncing around for years, and it’s really a painful experience to say the least. The actual fact is that you can’t help but cry out in your mind, seborrheic dermatitis, what am I going to do with you? The actual fact is that you can find a lot of people who are not able to get a good deal on this kind of things. It appears as dark red or yellow-red spots with greasy scales on the surface, often with itching, and in severe cases, oozing, vesicles and crusts. Seborrheic dermatitis can be divided into two categories: dry and wet according to the lesion performance. The dry type is mostly erythematous desquamative damage, while the wet type is mostly papules and blisters, which can produce vesicles, oozing, and yellow scabs after scratching. Itching is often unbearable, and the disease is slow and recurrent. The lesions are usually found in the seborrheic area and are often confined to the scalp, but in severe cases they may develop on the face, nasolabial folds, eyebrows, eyelids, middle of the chest and back, umbilicus and groin or armpits. The lesions begin as small follicular papules and gradually fuse into yellowish-red patches of varying size, covered with greasy scales and crusts. The clinical manifestations vary depending on the location and the severity of the damage. 1. Scalp. Often erythematous or follicular papules, may have small flakes, part of the surface may have greasy yellow scabs, hair dry, fine, thinning. 2, face, ears, behind the ears and neck. It often spreads from the head and appears as white scales or yellowish-red, greasy scabs. Diffuse erythema and desquamation in and around the eyebrows, with sparse eyebrow hair due to scratching. The eyelids are involved as blepharitis, and in severe cases, vesicles may develop. Behind the ear may show flushing, vesicles and chancroid, either unilateral or bilateral, mostly in girls and young women, and seborrheic otitis externa mostly in elderly patients. 3. Beard. Mostly seen in middle-aged men, the follicular opening is mildly red and swollen with small light brown crusts. Some manifest as follicular opening pustules with greasy scales and bright red around the base. 4.Torso. It is common in men over 20 years of age, usually on the forehead and between the scapulae, starting as small reddish-brown follicular papules covered with greasy scales, gradually forming round or oval light red patches with clear boundaries, which can be fused into a ring or map-like, etc. The surface may have greasy fine scales. 5.Folded part. Commonly found in the armpits, groin, under the breast and umbilicus, mostly seen in 30-50 years old, especially in obese middle-aged people. The lesions appear as well-defined erythema with greasy scales. The lesions may develop due to local sweating, secondary infection, or improper treatment. When the genitalia are involved, circular erythema and scaling and skin peeling can be formed, showing subacute eczema or psoriasis-like performance, without the typical characteristics of seborrheic dermatitis. 6. Extremities. The extensor side of the extremities is more common than the flexor side, manifesting as yellow-red or light-red patches, due to scratching, can form vesicles and resemble eczema. 7.Infant seborrheic dermatitis. 2-10 weeks after birth, infants, scalp, forehead, ears, eyebrows, nasal and cheek furrows and folds appear round erythema, clear borders, covered with scales, erythema can be extended and fused with sticky greasy crust, between the vesicles oozing, inflammation is more prominent, symmetrical occurrence, slightly itchy, generally children can be cured in 3 weeks to 2 months. If it persists, it is often complicated by atopic dermatitis in infants and can also be secondary to bacterial or Candida infections. Infants do not have the hair follicle damage and seborrhea of adults. Seborrheic dermatitis is clinically variable, with some confined to the head; others are generalized. Erythroderma, folliculitis, boils, and lymphadenitis can also result from repeated scratching and inappropriate treatment. The seborrheic dermatitis should be diagnosed and treated in time; the diet should be light, avoiding spicy and stimulating food and too greasy food; avoid abusing skin care products on the affected area, so as not to harm the skin’s own water-oil balance function and cause disorders of skin water-oil metabolism; pay attention to a reasonable diet!