Why Do My Feet Smell Sour?

Sour, pungent foot odor is often a sign that bacteria are building up on your feet. While some foot smell is normal, especially if you’ve been active, a consistently sour smell could indicate an underlying issue. Here’s an overview of some of the common causes of sour-smelling feet and what you can do about it.

Excessive Sweating

Sweat itself is odorless. But when your feet sweat more than usual, the moisture creates an ideal environment for bacteria to multiply rapidly. The bacteria feed on the sweat and produce unpleasant waste products that cause foot odor. This excess moisture also softens the skin, allowing it to absorb more of the smelly bacterial waste.

So if you notice your feet sweating excessively, especially if accompanied by a sour smell, the culprit is likely hyperhidrosis (excessive sweating). This condition can result from hormonal changes, health conditions like diabetes, or simply your genetics. Wearing unbreathable shoes and socks only exacerbates the problem.

To combat sweaty smelly feet, try these tips:

  • Wear moisture-wicking socks to absorb sweat and keep feet dry
  • Use antiperspirant or alum powder on feet to curb sweating
  • Apply antibacterial foot spray after showering to control bacteria
  • Use a dehumidifier and air conditioner to reduce humidity and sweat
  • Change socks at least twice a day when you sweat a lot
  • Consider prescription strength antiperspirants or other hyperhidrosis treatments

Fungal Infections

If your feet have a particularly pungent, cheesy odor, the cause may be a fungal infection. Skin fungi like athlete’s foot thrive in the warm, damp environment inside shoes and socks. As they multiply, they produce irritating acids that break down the skin and cause smelly odor. Fungal toenail infections can also contribute to foot odor.

To treat a fungal infection:

  • Apply over-the-counter antifungal creams, sprays or powders daily
  • Use antifungal soap when bathing and wash socks in hot water with fungicidal detergent
  • Disinfect shoes and socks with antifungal sprays or UV light cleaners
  • Exfoliate feet regularly with a foot scrub to remove dead skin and fungi
  • Apply foot powder inside shoes to absorb moisture and sweat
  • Consider prescription oral antifungal medication for stubborn or recurring infections

Bacterial Overgrowth

Our feet host thriving communities of bacteria naturally. But when their numbers get out of control, the bacteria feed on dead skin cells and sweat residue, producing noxious metabolic wastes. This is what causes common foot odor. Certain strains of bacteria produce more potent waste products that give feet a particularly sour, vinegary smell.

To counteract bacterial overgrowth:

  • Wash feet thoroughly with antibacterial soap and rinse well, including between the toes
  • Exfoliate feet regularly to remove dead skin cells and bacteria
  • Apply antibacterial foot spray after washing
  • Dust antibacterial foot powder inside shoes and socks
  • Wear clean socks daily to avoid transferring bacteria back to feet
  • Alternate shoes regularly to allow them to fully dry out
  • Disinfect shoes periodically with UV light or antimicrobial sprays

Poor Hygiene

Failing to properly cleanse your feet can allow odor-causing bacteria to flourish. Infrequent washing, not scrubbing between toes, rewearing socks, and not cleaning shoes can compound the problem. Harsh soaps can strip away protective oils, drying out the skin and allowing more bacterial waste absorption.

Practice good foot hygiene habits:

  • Wash feet daily with a gentle antimicrobial soap
  • Pay close attention to cleaning between toes
  • Exfoliate feet periodically to remove dead cells and bacteria
  • Rinse feet thoroughly after washing and dry well
  • Allow shoes to air out fully between wears
  • Disinfect shoe interiors frequently to kill bacteria
  • Change socks daily and wash them in hot water

Footwear Issues

What you put on your feet can also influence foot odor.Tight, non-breathable shoes prevent ventilation and create a humid environment. Plastic shoes and rubber boots also lock in sweat. Bacteria thrive in this moist, enclosed space. Abrasive seams and irritating materials can further exacerbate odor by damaging skin.

Choose footwear carefully:

  • Select shoes made of breathable natural materials like leather or canvas
  • Avoid plastic, rubber, and other occlusive materials
  • Make sure shoes aren’t too tight – allow a thumb’s width in front of toes
  • Alternate different pairs of shoes to give them time to dry out
  • Disinfect shoe interiors frequently with UV, ozone, or antimicrobial sprays
  • Use antifungal shoe powders and insoles
  • Wear moisture-wicking socks to absorb sweat
  • Go barefoot when possible to give feet a breather

Medical Conditions

In some cases, persistently smelly feet may result from an underlying medical issue. Problems like diabetes, athlete’s foot, hyperhidrosis, and hypothyroidism can all increase foot odor. Fungal toenail infections, eczema, and yeast overgrowth may also play a role.

See your doctor if you have severe or long-lasting foot odor to rule out related health conditions. Treating the source problem will often resolve the smelly feet as well. Your doctor can also check for less common foot odor causes like bromodosis, pitted keratolysis, and methane-producing bacteria.

Sour-smelling feet can be stressful and embarrassing, but don’t despair. With consistent foot hygiene, breathable footwear, and antifungal treatments, you can get foot odor under control. Pay attention to any worsening of symptoms or related changes, as they may indicate it’s time to see a podiatrist or dermatologist. With some diligent foot care, you’ll be confidently putting your best foot forward.