Healthy, athletic adolescent male with lesion under toenail

What’s your diagnosis?

A healthy, athletic 17-year-old male was seen by his primary physician with complaints of the gradual onset of a lesion under his right great toenail.

James H. Brien, DO

It was described as beginning with a very thin white line from the forward edge of the nail to approximately halfway toward the matrix. Over the next few weeks, it became wider with yellowish-brown discoloration and apparent separation from the nailbed but not involving the matrix of the nail, as shown in Figure 1. His primary diagnosed onychomycosis and prescribed topical miconazole 2% tincture, to be applied under the nail with a dropper or a small brush (included in the bottle) twice a day, and referred the patient to the infectious disease clinic for follow-up.

Figure 1. The right great toe of a 17-year-old male with a slow growing lesion under the nail, diagnosed as onychomycosis. Image: James H. Brien, DO

The patient’s past medical history is positive for having had bilateral “athlete’s foot” during football season a year earlier, which was successfully treated with topical miconazole for 3 weeks. He also recently contracted Epstein-Barr virus (EBV) infectious mononucleosis that was complicated with hepatitis, with liver enzymes still mildly elevated. He is otherwise healthy with immunizations up to date. His family history is positive for his father having been treated for a toenail infection with an oral medication 2 years earlier.

When he was seen in the infectious diseases clinic 17 days later, the toenail infection appeared somewhat improved from the initial picture, as shown in Figure 2. However, the medication appeared to result in some minor, asymptomatic inflammation of the surrounding skin, as shown.

Figure 2. Two weeks later, revealing some improvement but also some surrounding inflammation of the skin. Image: James H. Brien, DO

What’s your diagnosis?

A. Fluconazole 200 mg daily for 3 months

B. Itraconazole 200 mg twice-daily pulse therapy for 7 days/month for 3 months

C. Continue topical miconazole as ordered

D. Terbinafine 250 mg daily for 3 months

Answer and discussion:

The best answer is C, continue miconazole 2% drops under the nail bed as shown in Figure 3, taken 6 weeks after starting the drops, using the application brush included in the bottle of miconazole, revealing continued visual improvement. There are a couple of reasons for continuing topical therapy: 1) It visually appears to be working; and 2) the patient recently had EBV hepatitis, from which he has not completely recovered. All the oral antifungal agents listed for this condition require monitoring of the liver enzymes, even if there is no history of hepatitis. Virtually all experts consider it a contraindication to using them in the face of any liver disfunction, or at least using them with very close monitoring of the enzymes, on a case-by-case basis.

Figure 3. Six weeks later, showing the application of the miconazole 2% tincture with the included small brush. Image: James H. Brien, DO

After 4 months of topical treatment of this patient, the infection appeared to be essentially resolved and treatment was stopped. Two weeks later, the patient was seen again, revealing marked improvement of inflammation of the surrounding skin (Figure 4). The patient was instructed to return for any concerns of a recurrence, but was not seen again.

Figure 4. There is no visual evidence of the initial infection, with marked improvement of the inflammation. Image: James H. Brien, DO

Some experts categorize onychomycosis into four types: 1) distal subungual; 2) proximal subungual; 3) white superficial; and 4) candidal. This patient had distal subungual onychomycosis, with the separation of the nail from the nail bed (onycholysis), making it suitable for topical therapy. With Trichophyton species leading the list of dermatophytes causing onychomycosis, 2% topical miconazole is a reasonable choice, especially in a case such as this: relatively early with nail separation from the nail bed, and no matrix involvement — and elevated liver enzymes. Topical miconazole can be easily applied between the nail and the nail bed, and is usually effective in such a case. Other alternatives for more advanced cases may include surgical removal or various regimens of oral antifungal therapy, such as terbinafine or itraconazole for several months, but again, only if there is no preexisting liver disease.

In contrast to the patient presented, in May 2013, I showed a case of a healthy 15-year-old boy with fairly severe bilateral onychomycosis of multiple toes (Figure 5). Due to the severity, a culture was done, revealing Trichophyton species, which responded well to oral, pulse therapy with terbinafine (7 days per month for 6 months), with excellent results (Figure 6, post-treatment).

Figure 5. A 15-year-old boy with severe onychomycosis of multiple toes on both feet. Image: James H. Brien, DO

Figure 6. The same boy as in figure 5, with resolution of severe onychomycosis of multiple toes after 6 months of pulse therapy with terbinafine. Image: James H. Brien, DO

Lastly, some toenails can become thickened and distorted from repeated trauma, often seen in runners and ballet dancers (Figure 7, a nondiscolored, thickened second toenail of a marathon runner). The treatment (if any) might be offered by a podiatrist, but is likely permanent. Prevention is the best management and can be achieved by wearing properly fitted good running shoes, with more room in the toe box. I would advise that before taking up running for sport or exercise, if there is any question of toe problems such as a second toe being longer that the first, that a visit with the podiatrist be made. It might save a lot of trouble later.

Figure 7. Second toe of the right foot of a marathon runner, showing thickening from repeated trauma. Image: James H. Brien, DO

For a quick but thorough review of this somewhat confusing subject, I recommend the following free online resources:

• Elewski BE Clin Microbiol Rev. 1998;doi:10.1128/cmr.11.3.415.

• Stat Pearls, January 2024; Onychomycosis by M.A. Bodman, H.A. Syed and K. Krishnamurthy at the following NIH site: https://www.ncbi.nlm.nih.gov/books/NBK441853.

Columnist comments:

To all of you who read this column, I feel that thanks are in order. At the American Academy of Pediatrics National Conference & Exhibition in Orlando, Florida, on Sept. 30, I was given the 2024 Award for Lifetime Contribution in Infectious Diseases Education. I was aware of this award, which was started in 2004, with Dr. George McCracken, MD, FAAP, being the first recipient (see link below). The list goes on to read like a “who’s who?” of giants in the field. I do not think I am close to being a “giant.” However, I do think that after 36 years of writing this column, and perhaps by a bit of serendipity, I have been placed in the company of these outstanding pediatricians, all of whom I have looked toward to pattern my career.

Image: James H. Brien, DO

So, to you, the readers of this column, I simply say, “Thanks.” I am not quite ready to quit yet, and because of you and this recognition, I may keep writing till I drop. Please keep in touch.

To view past recipients of the award, click this link.