The white stuff on the armpit hair is usually mainly sweat crystals, but also may be armpit hair ringworm, once found need to timely medical treatment. Sweat glands are more developed in the heat or after strenuous exercise will usually secrete a lot of sweat, due to sweat contains a lot of salt, at the same time, the armpit will also secrete part of the oil, so if not cleaned up in time will be in the armpit hair above the formation of crystals, so usually should pay more attention to personal hygiene, as far as possible to wear breathable and loose clothing. In addition, because of the summer sweating more, if not timely cleaning easily lead to bacterial growth of armpit hair ringworm, often can be manifested as armpit hair on the white or yellowish crystals, long-term hair will be gradually damaged, lose luster. The specific need to go to the hospital, clear cause of the disease, and then follow the doctor’s instructions for treatment.