US Pharm. 2013;38(6):51-54.
ABSTRACT: Superficial fungal infections commonly affect the hands
and feet. While various dermatophytes can lead to infection,
Epidermophyton, Microsporum, and Trichophyton tend to cause the majority
of infections. Tinea pedis, tinea unguium, and tinea manuum are common
superficial fungal infections. Topical and oral antifungal agents, which
are the mainstay of therapy, often need to be used for 1 week to 4
months, depending upon the type and severity of the infection.
Pharmacists play an important role in educating patients about the
proper treatment of, and prevention strategies for, superficial fungal
Superficial fungal infections are caused by dermatophytes
(pathogenic fungi on the skin), which can infect the skin, hair, and
nails. Dermatophytes thrive on moist areas of the skin and may also be
found on clothing and towels and in the soil. About 20% to 25% of the
world population is infected with a dermatophyte.1 While various dermatophytes exist, three are known to cause the majority of fungal infections in humans: Epidermophyton, Microsporum, and Trichophyton.1
Two areas of the body commonly exposed to these pathogens are the hands and the feet. Tinea pedis (athlete’s foot) has a lifetime prevalence of approximately 70% and is often accompanied by tinea manuum (hands), tinea unguium (nails), or tinea cruris (groin).2
While tinea pedis, tinea manuum, and tinea cruris can be successfully
treated with OTC medications, tinea unguium typically requires
prescription medications. This article will focus on the clinical
features of fungal infections of the hands and feet, along with
potential preventive and treatment strategies.
Epidermophyton floccosum, Trichophyton mentagrophytes, and Trichophyton rubrum are
common causes of tinea pedis. Although contact with infected people,
animals, or fomites (inanimate objects capable of harboring infectious
agents) are obvious sources of fungal transmission, several other
factors promote the growth of tinea pedis: living in a warm or moist
climate, occlusive footwear, excessive sweating, community showers or
swimming pools, poor foot hygiene, and health conditions or medications
that suppress the immune system.2
Tinea pedis generally affects the superficial layer of the skin and
is often found between the toes, although it can infect the sides and
soles of the feet as well. Tinea pedis may be categorized as chronic
interdigital, moccasin, vesicular, or acute ulcerative. Chronic interdigital tinea pedis presents as macerations or fissures in the toe webs, with symptoms including malodor, pruritus, and burning of the feet. Moccasin tinea pedis
is characterized by diffuse scaling plaques on the soles and sides of
the feet and may be accompanied by mild inflammation and erythema. Vesicular tinea pedis
presents as small vesicles between the toes or on the soles of the feet
and tends to worsen in the summer. The presence of severe inflammation,
skin discoloration, macerations, and/or weeping ulcerations may
indicate acute ulcerative tinea pedis, which can be debilitating and lead to bacterial superinfections if not treated appropriately.2-5
With all four types, the risk of developing other superficial fungal
infections (such as tinea unguium) increases if the condition is not
properly treated. Beyond foot examination, diagnosis should be confirmed
by a potassium hydroxide (KOH) preparation used to visualize the scales
under a microscope, or (less commonly), by a fungal culture.3,4
The goals of tinea pedis therapy include symptom relief, fungus
eradication, and prevention of future infections. Topical antifungals,
which are considered first-line treatment for fungal skin infections of
the foot, are readily available as nonprescription products. Most of
these agents are applied once or twice daily, with a treatment duration
of 1 to 4 weeks.6 For more severe cases or if topical therapy has failed, oral prescription therapy may be employed. See TABLES 1 and 2 for a summary of products commonly used to treat tinea pedis.
A literature review reveals strong evidence that topical terbinafine
(an allylamine) and butenafine (an allylamine derivative) produce high
cure rates.7 These agents are considered fungicides, since
each inhibits squalene epoxidase, the enzyme responsible for
synthesizing the fungal cell membrane. The topical azole antifungals
clotrimazole and miconazole hinder fungal cell wall synthesis by
blocking the formation of ergosterol. For the most part, these agents
are fungistatic and, as a result, may be less effective than the
allylamines.6,7 However, azole therapy cure rates increase
with a longer treatment duration. In fact, azole treatment for 4 weeks
has similar outcomes to allylamine therapy for 1 week.7,8 After an appropriate treatment duration, topical azoles and allylamines reach cure rates of about 72% and 80%, respectively.9
Prescription topical therapies include sertaconazole, econazole,
ketoconazole, naftifine, and ciclopirox. As noted, systemic therapy may
be needed for severe cases or if topical therapy has failed.
Prescription oral terbinafine, itraconazole, and fluconazole have
demonstrated efficacy for tinea pedis.3,10,11 Fluconazole,
however, is not FDA approved for any type of tinea infection. Another
oral agent that may be used to treat tinea pedis is griseofulvin.10
Nevertheless, terbinafine is more effective than griseofulvin, and the
efficacies of terbinafine and itraconazole are comparable.12
Although self-treatment of tinea pedis is generally well tolerated
and safe for most patients, patients with a history of diabetes,
immunodeficiency, or signs of systemic infection should be referred to
their primary care physician. It is important to note that tinea pedis
presenting with inflammation or as the wet, soggy type may require the
use of an astringent solution (e.g., Burow’s solution) prior to
initiation of antifungal therapy.2 Burow’s solution may be
applied to the affected area for 20 minutes two to three times daily, or
as recommended. Although antifungal creams and solutions are better
treatment options since they are rubbed directly into the skin, sprays
and powders may be better formulations for prevention.2
Preventive strategies may prove beneficial, especially since up to 70% of patients experience recurrences.13
Several nonpharmacologic strategies may be used to help prevent initial
or recurring fungal foot infections. Because dermatophytes prefer a
warm, moist environment, it is important to keep the feet cool and dry.
Approaches include changing the socks more frequently, wearing cotton or
wool socks, and using nonocclusive footwear (e.g., such as sandals)
whenever possible. Because tinea pedis is transmittable from person to
person, contact with infected individuals should be avoided, and
protective footwear should be worn in public showers. The skin should be
washed with soap and water on a daily basis and dried thoroughly.2
The feet should be dried last, or a separate towel should be used for
the feet. Any potentially infected clothing should be washed in hot
water. Another prevention strategy is to sprinkle nonmedicated powder
inside the shoes to limit moisture.5 Currently, the only
FDA-approved active ingredient for tinea pedis prevention is tolnaftate.
Available as a cream, powder, solution, or spray, tolnaftate should be
applied once or twice daily.2
Tinea unguium, often referred to as onychomycosis, is an infection of nail tissue of the hands or the feet. T rubrum and Trichophyton interdigitale are
the common dermatophytes known to cause tinea unguium. Nondermatophytes
account for the remainder of infections, notably yeasts from Candida species, as well as molds from Fusarium and Acremonium species.14
Risk factors for onychomycosis include older age, swimming, trauma to
the nail, diabetes, immunosuppression, living with someone with
onychomycosis, and tinea pedis.15
There are three forms of onychomycosis: distal subungual, superficial white, and proximal subungual. Distal subungual onychomycosis
is the most common form, with the big toe usually the first nail to be
affected. This form involves the end third of the nail farthest away
from the cuticle and begins with a whitish, yellowish, or brownish
discoloration of the nail. The discoloration eventually spreads to the
entire nail and extends slowly to the cuticle. The discoloration is due
in part to keratinous debris between the nail and the nail bed. A
patient may present initially with hyperkeratosis of the nail bed, which
may lead to onycholysis (separation of the nail from underlying
tissue). Onycholysis causes pain, which may prevent the patient from
being able to perform typical activities of daily living. Superficial white onychomycosis infects the entire top surface of the nail and has a flaky appearance. Proximal subungual onychomycosis,
which is relatively rare, occurs mostly in immunocompromised patients;
it presents with a seemingly deeper infection that occurs under the nail
near the cuticle and extends distally.16 Unless treated properly, onychomycosis persists indefinitely.
It is important to recognize the presence of fungus before antifungal
therapy is initiated. A variety of presentations exist that could lead
to a differential diagnosis, including psoriasis, iron deficiency,
eczematous conditions, trauma, yellow nail syndrome, periungual squamous
cell carcinoma, and lichen planus. Studies have indicated that
onychomycosis is responsible for only 50% to 60% of abnormal-appearing
nails.17 The examiner must take into account the number of affected nails, as well as symmetry, pain, and other nail characteristics.16 Onychomycosis is most readily confirmed using a KOH preparation for histologic examination.18 Treatment should be initiated upon confirmation.
Topical and systemic therapies for onychomycosis exist; however, studies indicate that systemic therapies are more effective.10
Topical antifungal creams do not adequately penetrate the nail bed and
are not considered appropriate. However, an antifungal topical in the
form of a nail lacquer (e.g., ciclopirox) is an option, especially in
patients in whom oral therapy is contraindicated. The combination of
oral terbinafine and topical ciclopirox has not been shown to provide
greater efficacy.19,20 Evidence supports the use of oral
terbinafine or itraconazole for 6 to 8 weeks for fingernail
onychomycosis. Toenail onychomycosis requires a longer duration of
therapy (12-16 weeks for terbinafine, or continuous daily dosing with
itraconazole for 12 weeks).16 In patients with onychomycosis,
fluconazole 150 mg to 300 mg once weekly has been effective, but less
effective than terbinafine or itraconazole.21 Griseofulvin,
another treatment option, has been associated with lower clinical cure
rates—as well as with recurrence—compared with terbinafine.22 TABLES 1 and 2 include a summary of available treatment options for onychomycosis.
Patients with onychomycosis should be educated about proper hygiene
and lifestyle modifications in order to prevent relapse and recurrence.
Patients should be encouraged to adequately trim the toenails directly
across the toe with minimal curvature, as well as to avoid walking
barefoot in damp areas.23 The feet should be kept clean and
dry, and an emollient may be applied to areas of compromised dry skin
where a fungal infection may be more probable. Adequate footwear that
minimizes humidity should be worn, and should later be discarded upon
significant wear and tear.16,23
Tinea manuum, sometimes referred to as two feet–one hand syndrome, is similar to moccasin tinea pedis and often develops after the occurrence of tinea pedis or tinea unguium.24,25 The same fungal species that cause tinea pedis and tinea unguium also can result in tinea manuum.25
Typically, the hand used to scratch the foot with the rash is affected.
The palm appears hyperkeratotic, with a fine white scale emphasizing
the normal lines of the hand. The dorsal surface of the hand may exhibit
a classic ringworm appearance. Tinea manuum may mimic eczema, contact
dermatitis, palmar psoriasis, or dryness of the hand. Overall, tinea
manuum occurs less frequently than either tinea pedis or tinea unguium.
Preventive and treatment strategies, which are the same as for tinea
pedis, are summarized in TABLES 1 and 2.25
Superficial fungal infections of the hands and feet are manageable
conditions with a favorable prognosis when treated appropriately.
Topical and oral antifungals continue to be the mainstay of therapy and
often need to be used for 1 week to 4 months, depending upon the type
and severity of fungal infection. It is important to counsel the patient
regarding the potential for recurrence despite adequate adherence and
symptom resolution. Prevention strategies should be encouraged in order
to minimize the risk of future infections.
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