Suddenly smelly feet may be caused by physiological phenomena, athlete’s foot, metabolic diseases and other reasons. 1. Physiological phenomenon: if the feet sweat a lot, a large amount of sweat will lead to the environment of the humidity, promote the fermentation of sweat, which produces a large number of bacteria, leading to the phenomenon of feet suddenly become smelly. 2. Tinea pedis: due to the feet are infected by fungi, and under the stimulation of the fungi easily cause the feet to odor, itching and other symptoms. Common fungi include red trichophyton, flocculent epidermolysis bullosa and so on. 3. Metabolic diseases: such as hyperthyroidism, diabetes, etc., due to abnormal metabolism, the body will increase sweating, resulting in an increase in foot bacteria, fungi, which triggered the feet suddenly become smelly. In addition, it is recommended that patients with suddenly smelly feet go to the hospital in a timely manner, and follow the doctor’s instructions for treatment to avoid delays.