Foot infections are often mild and easily treated at home, particularly fungal ones.
Others can get worse and spread into the bloodstream, especially bacterial ones, and require aggressive medical treatment.
The roots of the fungus can easily penetrate damp, softened tissues.
Verywell/Brianna Gilmartin
Infection can occur by simply touching a moist, contaminated surface with your foot.
Fungal foot infections can be persistent and hard to treat, but they are rarely life-threatening.
Athlete’s foot is highly contagious and easily passed through contaminated floors, towels, footwear, or clothing.
Reproduced with permission from ©DermNet NZwww.dermnetnz.org2022
Toenail Fungus
Onychomycosisis the medical term for a fungal toenail infection.
Also known astinea unguium, it often occurs alongside tinea pedis but can occur on its own.
Symptoms of toenail fungus include:
Onychomycosis can be diagnosed by a visual examination of the toenail.
Your healthcare provider may order a KOH test to confirm the diagnosis.
Tissue cultures from nail trimmings can help identify the specific fungus.
Onychomycosis is notoriously difficult to treat, partly because topical creams can’t penetrate the nail plate.
Most bacterial infections are established when a bacteria enters a sore, cut, or abrasion on a foot.
The most common causes areStaphylococcus aureus(staph infection) andCorynebacterium,both of which naturally populate the feet.
Erythrasma
Erythrasmais a bacterial infection frequently mistaken for a fungus.
It is mainly caused byCorynebacterium minutissimumand is most common in people with diabetes or obesity.
On light skin, erythrasma causes pinkish or reddish patches that gradually turn brownish and scaly.
The lesions can be harder to spot on dark skin.
Erythrasma can often be diagnosed with aWood’s lampthat makes the bacteria look coral-pink under ultraviolet light.
Foot abscesses are often because of puncture wounds or hair follicles that become infected.
They’re similar toboilsbut involve deeper tissues.
There may also be generalized achiness and low-grade fever.
In some cases, an abscess can be extremely firm (indurated).
Abscesses are most often caused byStaphylococcus aureus,but other bacteria can also cause deep tissue infection.
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Reproduced with permission from DermNet NZwww.dermnetnz.org2022
Abscesses can often be diagnosed with a physical exam.
Your healthcare provider may order abacterial cultureto identify the bacterial culprit and prescribe the most effective antibiotic.
Treatment usually involves thedraining of the abscessfollowed by a course of oral and/or topical antibiotics.
An OTC painkiller likeTylenol (acetaminophen)can reduce pain and fever.
Septicemia, in turn, can trigger a potentially, life-threatening inflammatory reaction known assepsis.
Simple cases of cellulitis may be treated withbroad-spectrum antibioticsfor between five and 14 days.
Serious cases may require hospitalization with intravenous (IV) antibiotics and fluids.
When to Seek Emergency Care
Cellulitis is always a medical emergency.
If you see a red streak moving up your foot, get immediate medical help.
If the skin on your foot is cut or scraped, wash it immediately with soap and water.
Then cover it with a sterile bandage.
If your foot is prone to dryness and cracking, use a petrolatum-based foot cream to soften the skin.
Summary
Fungal foot infections include athlete’s foot and onychomycosis (toenail fungus).
They’re easy to spread but can be readily treated with topical or oral antifungals.
Bacterial foot infections include erythrasma, abscesses, and cellulitis.
Oral or topical antibiotics can clear them up.
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doi:10.7759/cureus.10733
Kolar SL, Liu GY.Targeting bacterial abscess formation.EBioMedicine.2016;12:16-17. doi:10.1016/j.ebiom.2016.10.017
Centers for Disease Control and Prevention.About cellulitis.
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