Vitamins are essential for human life activities and are generally consumed from food, except for a few vitamins that can be synthesized internally by the body. Vitamin deficiency can often cause the corresponding dermatological manifestations. Examples are as follows: 1, vitamin A: deficiency can appear in the skin, especially the arms, legs, shoulders under the abdomen skin roughness, dryness, scaly state and other keratinization changes, peripapillary keratosis, dry eyes and corneal softening. Others such as nails appear deep and obvious white line hair dry, memory loss, mood irritability and insomnia, dark adaptability decline, night blindness, oral, digestive, respiratory and genitourinary tract mucosa loss of moist, softness, so that bacteria are easy to invade, prone to serious diseases such as bronchopneumonia and children’s growth is hindered, affecting bone development and dental growth. 2, vitamin C: deficiency of early non-specific symptoms, generally manifested as drowsiness and weakness, easy bleeding gums, poor wound healing, transient pain in joints and muscles, etc.. The skin is prone to purpura and petechiae after collision; teeth may loosen and fall off due to sulcus necrosis; subperiosteal bleeding of the eye may make the eye protrude; intracranial bleeding may lead to sudden convulsions and shock, resulting in death. Vitamin C deficiency can lead to reduced chemotaxis and bactericidal function of white blood cells, reduced synthesis of immune antibodies, weakened antiviral ability, easy to catch a cold and various infectious diseases. 3, niacin deficiency: can cause niacin deficiency (also known as pellagra or accompanying lager), showing dermatitis, diarrhea and dementia, but the most common dermatitis. Dermatitis mainly occurs on exposed areas of the body such as the back of the fingers, back of the hands, forearms, face, and neck and chest. The lesions start as symmetrical bright red patches with clear boundaries, resembling sun spots, with burning and slight itching; then the lesions change from bright red to dark red, brownish red or coffee; later the lesions become thick, hard, rough, cracked and pigmented, and finally atrophy occurs. In severe cases, large blisters can be formed, with severe redness and pain, and there can be secondary infections, forming pustules and occasionally ulcers. Similar symptoms can be seen in the axillae and scrotum, where the lesions often flare up or worsen in summer, and reduce or subside in winter. Patients often develop stomatitis, tongue inflammation or vulvodynia, with bright red or scarlet tongue, the appearance of Merle’s tongue inflammation, black hairy tongue can also be observed, and a self-conscious burning sensation. Therefore, it is advisable to pay attention to a balanced diet and to increase the proportion of fruits and vegetables in the diet appropriately to meet the body’s intake of vitamin classes.