Sudden foot odor can be caused by a variety of reasons, generally consider that usually do not pay attention to personal hygiene and habits, fungal infections, long-term in a humid environment and other reasons. 1. Not paying attention to personal hygiene and habits: when the human body long time exercise and shoes and socks are not breathable, can lead to feet sweat gland large secretion, then can be manifested as feet suddenly become smelly. 2. Fungal infections: Fungal infections, commonly known as foot odor, may be infected by sharing shoes and socks with other people, or by frequently scratching the feet when suffering from ringworm. Erosion, itching and foot odor can occur. 3. Being in a humid environment for a long time: when the human body is in a humid environment for a long time due to work, the bacteria in the feet can multiply, which can lead to the occurrence of foot odor. Need to go to the hospital, a clear diagnosis of the cause of the targeted treatment, you can not just randomly use drugs.