Most of the underarm itch is caused by sweating in the area, due to the distribution of a large number of sweat glands and parietal sweat glands, and these large number of sweat glands and parietal sweat glands secretion of sweat can not be effectively and timely removal, in this place is very easy to secondary some bacterial or fungal infection. At the same time, the sweat itself will be easy to impregnate, it is easy to secondary localized itching of the skin. Therefore, it is usually felt that the skin of the armpit has an itchy feeling. This kind of itching, on the one hand, is the stimulation of sweat, on the other hand, there may also be sweat associated with bacterial or fungal infection, resulting in a kind of irritating itching.