When to see a doctor
In some cases, foot odor can be so foul or persistent that a visit to the doctor is necessary. "If [the previous] steps don’t work, see a podiatrist or dermatologist, who might prescribe a stronger antifungal medication or perform tests to determine an underlying cause for the excessive sweating," suggests Dr. Kosinski.
Occasionally, a funky smell can be a sign of a larger medical problem, "especially in a person with any immune compromising medical condition," says Dr. Schwartz. "It is critical to be sure to look for a possible cut or wound of the skin or between the toes, any increased redness, or swelling. A severe bacterial infection of the skin or soft tissue will usually produce a terrible odor."
Diabetics should be on particular lookout for foot odor: "If you have diabetes, visit a doctor at the first sign of odor, which may be a sign of a more serious problem," says Dr. Kosinski. "Fungal and bacterial foot infections can progress quickly and become more severe in people with diabetes."