Sudden odor in the armpit is mainly related to two reasons: bad hygiene habits and armpit odor. 1. Bad hygiene habits: in the hot summer or after exercise, sweat glands will secrete a lot of sweat. If you have bad hygiene habits, the protein in the sweat accumulates in the armpit for a long time, and after fermentation, the armpit will volatilize the odor. 2. Armpit odor: common in women, usually with a family history. When the organic matter in the sweat gland secretion is decomposed by bacteria, a special flavor will be formed, because this flavor is similar to the gas discharged from the anus of foxes, also known as fox odor. If the odor appears in the armpit, the light can be reduced to a certain extent by taking baths and changing clothes diligently, keeping the skin clean and hygienic, dry and clean, or externally using perfume to cover the odor. If the condition is more serious, it is recommended to go to the dermatology department of regular hospitals, and choose laser or minimally invasive surgery and other treatments under the guidance of doctors.