Foot odour is a common foot skin issue. When you have sweaty feet, the excess foot perspiration soaks the lining of your shoes and socks, and creates an environment for bacteria, which can grow and cause a bad odour. Smelly feet and/or shoes especially when you first take your shoes off are the most common signs of foot odour. People who wear poorly ventilated shoes, synthetic or non-leather boots, or non-wicking socks made of polyester or nylon may be more likely to have persistent foot odour. Dr. Scholl