Fungal Nail Infections

Definition

Fungal nail infections are common infections of the fingernails or toenails that can cause the nail to become discolored, thick, and more likely to crack and break. Infections are more common in toenails than fingernails. 1 The technical name for a fungal nail infection is “onychomycosis.”
Composite image. Onychomycosis due to Trichophyton rubrum, right and left great toe. Tinea unguium.

Symptoms

Nails with a fungal infection are often:

  • Discolored (yellow, brown, or white)
  • Thick
  • Fragile or cracked

A fungal nail infection usually isn’t painful unless it becomes severe.

Some people who have fungal toenail infections also have a fungal skin infection on the foot, especially between the toes (commonly called “athlete’s foot”).

How does someone get a fungal nail infection?

Fungal nail infections can be caused by many different types of fungi (yeasts or molds) that live in the environment. Small cracks in your nail or the surrounding skin can allow these germs to enter your nail and cause an infection.

Who gets fungal nail infections?

Anyone can get a fungal nail infection. Some people may be more likely than others to get a fungal nail infection, including older adults and people who have the following conditions: 2,3

  • A nail injury or nail surgery
  • Diabetes
  • A weakened immune system
  • Blood circulation problems
  • Athlete’s foot (ringworm on the foot)

Prevention

  • Keep your hands and feet clean and dry.
  • Clip your fingernails and toenails short and keep them clean.
  • Don’t walk barefoot in areas like locker rooms or public showers.
  • Don’t share nail clippers with other people.
  • When visiting a nail salon, choose a salon that is clean and licensed by your state’s cosmetology board. Make sure the salon sterilizes its instruments (nail clippers, scissors, etc.) after each use, or, you can bring your own. Please click here for more information about nail hygiene.

Diagnosis

Your healthcare provider may diagnose a fungal nail infection by looking at the affected nail and asking questions about your symptoms. He or she may also take a nail clipping to look at under a microscope or send to a laboratory for a fungal culture.

Treatment

Fungal nail infections can be difficult to cure, and they typically don’t go away without antifungal treatment. The best treatment for a fungal nail infection is usually prescription antifungal pills taken by mouth. In severe cases, a doctor might remove the nail completely. It can take several months to a year for the infection to go away.

Information for Healthcare Professionals

References
  1. Gupta AK, Jain HC, Lynde CW, Macdonald P, Cooper EA, Summerbell RC. Prevalence and epidemiology of onychomycosis in patients visiting physicians’ offices: a multicenter Canadian survey of 15,000 patientsexternal icon. J Am Acad Dermatol. 2000 Aug;43(2 Pt 1):244-8.
  2. Scher RK, Rich P, Pariser D, Elewski B. The epidemiology, etiology, and pathophysiology of onychomycosisexternal icon. Semin Cutan Med Surg. 2013 Jun;32(2 Suppl 1):S2-4.
  3. Gupta AK, Konnikov N, MacDonald P, Rich P, Rodger NW, Edmonds MW, et al. Prevalence and epidemiology of toenail onychomycosis in diabetic subjects: a multicentre surveyexternal icon. Br J Dermatol. 1998 Oct;139(4):665-71.
  4. Elewski BE. Onychomycosis: pathogenesis, diagnosis, and managementexternal icon. Clin Microbiol Rev. 1998 Jul;11(3):415-29.
  5. Hay RJ, Baran R. Onychomycosis: a proposed revision of the clinical classificationexternal icon. J Am Acad Dermatol. 2011 Dec;65(6):1219-27.
  6. Finch J, Arenas R, Baran R. Fungal melanonychiaexternal icon. J Am Acad Dermatol. 2012 May;66(5):830-41.
  7. Wilsmann-Theis D, Sareika F, Bieber T, Schmid-Wendtner MH, Wenzel J. New reasons for histopathological nail-clipping examination in the diagnosis of onychomycosisexternal icon. J Eur Acad Dermatol Venereol. 2011 Feb;25(2):235-7.
  8. Elewski BE, Leyden J, Rinaldi MG, Atillasoy E. Office practice-based confirmation of onychomycosis: a US nationwide prospective surveyexternal icon. Arch Intern Med. 2002 Oct 14;162(18):2133-8.
  9. Lipner S, Scher RK. Onychomycosis: current and future therapiesexternal icon. Cutis. 2014 Feb;93(2):60-3.
  10. Gupta AK, Paquet M, Simpson FC. Therapies for the treatment of onychomycosisexternal icon. Clin Dermatol. 2013 Sep-Oct;31(5):544-54.