An elderly man who lives in Gulou District, Fuzhou City, is a retired teacher. Usually, Jim’s hair is dyed just to cover up the gray hair, and her choice of hair dye is even more random, often just looking at the right price to use. The actual fact is that you can find itchy, blistered skin just after the Spring Festival. “The actual hair coloring may cause two kinds of dermatitis from the skin’s point of view, the hair dye contacting the scalp easily induces irritating dermatitis. Hair dye does not come into contact with the skin may also trigger allergic dermatitis.” According to experts, allergic dermatitis can lead to local skin erythema, blisters, itching and other symptoms. The general incidence of allergic dermatitis is not very high, which also has to do with the body’s constitution and the level of immunity. Severe allergic people can suffer from systemic allergies, such as respiratory cramps, and even life-threatening. Brand cannot be the key to choose. Nowadays, there are quite a lot of people who have dyed their hair, but consumers usually only pay attention to the brand and effect of hair coloring, and the most understood is only the effect on hair quality, such as dryness, split ends and so on. People basically do not use the ingredients as an indicator of choice, and it is unclear what ingredients hair dyes contain. There are even many people who believe that as long as they do not come into contact with the scalp there will be no health effects. “Hair dye component content indicators can not be ignored, its phenylenediamine should be reduced from 6% to 2%, hydrogen peroxide (hydrogen peroxide) from 10% to 4%, in order to meet international safety standards.” Experts pointed out that hair dyeing is not impossible, or you can choose according to your needs, but some allergic people, people who have had hair dye allergies, pregnant and lactating women, children, it is best not to dye hair. In addition, people suffering from blood diseases, hives, asthma, people using antibacterial agents, people with unhealed head and facial trauma or wounds, and couples preparing for childbirth should not dye their hair.