INTRODUCTION
Onychomycosis accounts for roughly 1/3 of all skin
fungal infections, and although onychomycosis is
common it is also often difficult to treat and can
have significant deleterious effects on patient’s quality of
life.1 Distal and lateral subungual onychomycosis (DLSO),
which is the overwhelmingly most common type of onychomycosis,
is thought to originate from direct extension and invasion
of dermatophytes infecting the plantar surface of the
foot (tinea pedis) into the nail bed. Dermatophytomas are a
feature seen in some DLSO infections and are characterized
by thick adherent fungal masses within and under the nail
plate. Dermatophytomas are particularly difficult to treat due
to their fungal framework and composition.2
Until recently, traditional therapeutic options for DLSO have
been comprised of mainly oral terbinafine and itraconazole,
and although these medications are commonly prescribed, they
have been associated with significant toxicities and drug-drug
interactions. Dermatophytomas are often recalcitrant to even
long courses of oral antifungal medications. In addition to severe
infection and presence of dermatophytomas, other host
factors associated with non-responsiveness to therapy include
advanced age, peripheral vascular disease (PVD), immunosuppression,
and concurrent psoriasis.3 Efinaconazole 10% solution
is a new FDA approved topical medication indicated for treatment
of DLSO. Here we report a case of an elderly patient with a
history of PVD and a dermatophytoma caused by Trichophyton
rubrum who was successfully treated with efinaconazole 10% solution.
The dermatophytoma resolved within 3 months and the
remaining onychomycosis infection was significantly improved
and on course for a cure with time. This represents the first case
of a dermatophytoma responding to a topical antifungal agent.
CASE REPORT
A 66-year-old man with a history of PVD, nonalcoholic steatohepatitis
(NASH), and a distant history of tinea pedis
treated with topical therapy, initially presented in 2012 for
treatment of onychomycosis involving the left great toe. At
that time, the patient had positive KOH scraping and culture
positive for T. rubrum from his left great toe. The patient was
initially treated for two months with oral terbinafine 250 mg
daily, but this treatment was discontinued because of lack of
efficacy and elevated liver function tests above the patient’s
baseline. A second attempt of systemic treatment was made
with one month of once weekly fluconazole 200mg; however
this was discontinued after 4 weeks because of continued
elevation of hepatic enzymes.
The patient continued to contact our office and expressed
interest in participating in a clinical trial. Without adequate
treatment, the patient’s onychomycosis progressed to include
a dermatophytoma and he was thus excluded from participating
in a clinical trial due to the severity of his infection.
In July 2014 the patient was brought back into clinic for further
treatment as efinaconazole 10% solution had recently been
approved for the treatment of onychomycosis. On presentation,
the patient’s left great toe had a 9 mm wide yellow-brown
streak extending from the distal nail edge to the proximal nail
fold with associated moderate hyperkeratosis of the nail bed
(Figure 1). All other toe and finger nails were unremarkable,
and there was no evidence of concomitant tinea pedis.
The patient was prescribed efinaconazole 10% solution and
was instructed to apply the medication once daily to the surface
of the affected nail as well as to the hyponychium, as
per label instructions. He was also advised to clip the onycholytic
nail to better allow penetration of the medication
into the nail bed and subungual space.
The patient followed up at week 12 and the dermatophytoma
was completely resolved and 3.5 mm of new healthy nail was
noted (Figure 2). The patient reported noting improvement as
early as week 3, however no photos were taken prior to the
