Fungal nail infection
Tim C olde Hartman and Eric van Rijswijk explain what you might cover in a 10 minute consultation in primary care
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 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.1
Fungal infection of the toenail
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.
We thank Mark van der Wel for reviewing the manuscript.
Competing interests: None declared.
Patient consent: Not needed (patient dead or cases are constructed scenarios or anonymised).
Provenance and peer review: Not commissioned; submitted with the encouragement of Els Licht (Email: e.licht@vumc.nl); externally peer reviewed.
This article was first published in the BMJ (2008;337:a429, 10.1136/bmj.39357.558183.94).
Tim C olde Hartman general practitioner
t.oldehartman@hag.umcn.nl
Eric van Rijswijk general practitioner Department of Family Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, Netherlands
Student BMJ 2008;16:370 | 10
