Fungal nail infection
BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.39357.558183.94 (Published 10 July 2008) Cite this as: BMJ 2008;337:a429
- 1Department of Family Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, Netherlands
- Correspondence to: T C olde Hartman t.oldehartman{at}hag.umcn.nl
- Accepted 13 April 2007
A 38 year old woman comes to you with a cosmetic problem in her toenails. She describes her nails as yellowish brown and crumbly and with detachment and thickening of parts of the nails. The problem appeared gradually, but she is now too embarrassed to wear open shoes. She wants to know whether it can be treated.
What issues you should cover
Key signs of fungal nail infections—The main changes in onychomycosis are nail thickening, discoloration, and onycholysis (separation of the nail plate from the nail bed). Onycholysis also gives a crumbly aspect to the nail.⇓
Causes and prevalence—In fungal nail infection dermatophytes invade the nail plate. The prevalence of the infection increases with age. Several studies report a prevalence of 15-20% in patients aged ≥40 years. In the general population the prevalence is 3-5%.
Patients requiring extra vigilance—Some patients (those with diabetes or poor peripheral circulation) are at risk of secondary bacterial infections. It is important to assess the effects and symptoms of the fungal nail infection in these patients.
Other dermatological problems—Because fungal nail infections are part of a larger group of dermatomycosis infections, you should ask about other dermatological problems. The presence of dermatomycosis elsewhere on the feet makes the diagnosis of fungal nail infection more likely. However, psoriasis and lichen planus may also cause nail problems that look like a fungal infection.
Previous treatments—Patients may already have tried topical agents bought over the counter. Systemic oral treatments are increasingly being advertised to the public.
Is it really a fungal infection?—Yellowish brown nails and crumbling do not always result from fungal infections. In only 20-50% of patients with clinically suspected fungal nail infection is a dermatophyte found in a culture. Other causes include direct trauma to the nail (wearing shoes that are too tight; nail biting), poor peripheral circulation, psoriasis, lichen planus, diabetes, or poor foot care.
Effects on quality of life—Fungal nail infections can have negative effects on the patient’s emotional, social, and work life. Sometimes patients complain about pain or discomfort in walking. They may feel unclean or ashamed or be fearful of transmitting the infection to family and other contacts.
Useful reading
Crawford F, Young P, Godfrey C, Bell-Syer SE, Hart R, Brunt E, et al. Oral treatments for toenail onychomycosis. Arch Dermatol 2002;138:811-6
Elewski BE. Onychomycosis: pathogenesis, diagnosis, and management. Clin Microbiol Rev 1998;11:415-29
Hart R, Bell-Syer SEM, Crawford F, Torgerson DJ, Young P, Russell I. Systematic review of topical treatments for fungal infections of the skin and nails of the feet. BMJ 1999;319:79-82
What you should do
Examination and diagnosis
Testing for dermatophytes is easy to do in general practice, although clinical diagnosis of fungal nail infection is difficult, as dermatophytes are present in only half of patients. Direct microscopic examination of small pieces of the nail after they have been soaked for one hour in 20% potassium hydroxide solution is needed (false negative rate 30-40%). The validity depends on the skills of the researcher. Sending nail and subungual debris for mycological culture testing increases sensitivity but may take several weeks.
Explanation and reassurance
Tell the patient that although fungal nail infections sometimes hinder patients’ emotional or social life, there is no absolute need for treatment. Discuss possible treatment options with her, including side effects, success rate of treatment, and recurrence rate (which is 22% after three years).
Treatments
Topical antifungal treatments—The active antifungal agent in these preparations is an imidazole, terbinafine, or a polyene. These drugs are slightly better than placebo, but treatment often fails because of their inability to penetrate the entire nail plate.
Systemic antifungal drugs—Itroconazol and terbinafine are effective systemic treatments. Continuous treatment for 3-4 months is successful in 50-80% of patients. However, side effects—such as headache, itching, loss of sense of taste, gastrointestinal symptoms, rash, fatigue, and abnormal liver function—can occur. Serious side effects, such as liver failure, are rare.
Cosmetic treatments—Nail filing and nail polish can help to lessen the cosmetic effects of detachment of the nail plate from the nail bed and thickening of the subungual region. A chiropodist may also be helpful in mitigating the effects.
Preventing further infections
Treating tinea pedis prevents the development of fungal nail infections. As certain public environments such as communal bathing places, locker rooms, and gymnasiums can harbour the infectious organisms, patients may benefit from wearing sandals or slippers in these areas.
Notes
Cite this as: BMJ 2008;337:a429
Footnotes
This is part of a series of occasional articles on common problems in primary care. The BMJ welcomes contributions from GPs.
We thank Mark van der Wel for reviewing the manuscript.
Funding: None.
Competing interests: None declared.
Provenance and peer review: Not commissioned; submitted with the encouragement of Els Licht (e.licht{at}vumc.nl); externally peer reviewed.
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