Toenail fungus infection in 15-year-old
A 15-year-old male was referred to the podiatry clinic for evaluation and treatment of toenail fungus infection involving several toes of both feet.
He was treated with scraping of the nails and the topical application of terbinafine (Lamisil AT, Novartis) twice daily for 30 days, followed by a “maintenance” phase of continued twice-daily cleaning, scraping and drying. After initial improvement, he noted that 4 months after completing the treatment regimen, the problem was worse than before and he was referred to the pediatric infectious diseases clinic. His medical history is that of an otherwise healthy adolescent male.
A complete examination was normal except for his feet, which revealed several yellowish, thickened nails on both feet as shown in Figures 1 and 2. A sample of the nail of the second toe of the left foot was clipped and sent for fungal culture.
Source: Brien JH
What’s Your Treatment?
A. Continue topical terbinafine for another month
B. Oral terbinafine daily for 7 days per month for 6 to 12 months
C. Oral griseofulvin for 6 months
D. Topical 8% ciclopirox for 3 months
This is a case of tinea unguium. Of these choices, a 6-month regimen of pulse dosing, using oral terbinafine (B), is my choice. This pulse dosing schedule works well, is less toxic to the liver and easier for compliance purposes. For children aged 4 years and older who weigh less than 25 kg, the recommended dose is 125 mg. For children who weigh 25 kg to 35 kg, the dose should be 187.5 mg. For children who weigh more than 35 kg, the dose should be 250 mg.
This is a rare condition in children aged younger than 12 years, so the majority will get the maximum of 250 mg given once daily. One could also use itraconazole at 2 mg/kg/day (200 mg maximum). With either drug, one should be aware of potential liver toxicity and drug interactions, on a case-by-case basis. Some experts recommend monitoring liver enzymes, at least during the initial month of treatment. Usually, 6 months of pulse treatment is long enough, although some may require up to 12 months, and even then, recurrences happen in up to 20%.
Most topical agents tend to not work well and have a high recurrence rate. This is in part due to the thickness of the toenail, but the newer ciclopirox nail solution works better because it penetrates deeper and is cidal to the common causes. However, most people, especially adolescents, will not comply with the recommended regimen of nail hygiene and topical application on each nail every day for 6 to 12 months. Also, it is less effective in reaching fungus in the more proximal parts of the nail.
Supplemental therapy should be done during the oral treatment phase and continued for “maintenance” indefinitely. This includes: 1) wash well and dry thoroughly and keep dry; 2) scrape off any areas that can be reached; 3) wear absorbent socks; and 4) routine use of an anti-fungal foot powder, such as Tinactin (MSD Consumer Care), Desenex (Novartis), Lotrimin AF (MSD Consumer) or Zeasorb AF. Some experts additionally recommend using topical terbinafine for variable periods of time. How well the maintenance therapy is done may correlate with the chances of recurrence.
Griseofulvin is the drug of choice for tinea capitis (Figure 3), but not for tinea pedis. It has been shown to be significantly inferior to the other choices noted above. However, because of experience, some may use it in younger children. Fortunately, toenail fungus infections are fairly uncommon in young children.
It is important to document the diagnosis, usually by culture, as some conditions may mimic tinea unguium, such as psoriasis, trauma (Figure 4, thickening from chronic trauma from marathon running), and other noninfectious causes of onychodystrophy.
The fungal culture of this patient grew Trichophyton species, the most common cause. He had a good response, as shown in Figure 5, at 8 months; showing near complete normalization of the nails. At the end of 8 months of treatment (nine pulses), the oral terbinafine was discontinued and good foot hygiene (maintenance) was reinforced to prevent recurrence. Fourteen months later, he remained infection-free.
Be on the lookout for an excellent general pediatric meeting at the Hyatt Regency Lost Pines Resort, near Bastrop, Texas; right on the Colorado River. It’s an excellent meeting, jointly sponsored by Texas Children’s Hospital and Baylor College of Medicine in Houston and McLane Children’s Hospital at Scott & White. This year it will be from July 11-13, with plenty of down time for family activities. I hope to see you there.
For more information:
James H. Brien, DO, is a member of the Infectious Diseases in Children Editorial Board, as well as Vice Chair for Education at The Children’s Hospital at Scott and White, and is the Associate Professor of Pediatrics at Texas A&M University, College of Medicine, Temple, Texas, can be reached at firstname.lastname@example.org.
Disclosure: Brien reports no relevant financial disclosures.