Assessment of Dermatophytosis Treatment Studies: Interpreting the Data
October 2015 | Volume 14 | Issue 10 | Supplement Individual Articles | 48 | Copyright © October 2015
Theodore Rosen MD
Department of Dermatology, Baylor College of Medicine, Houston, TX
Antifungal therapy has recently enjoyed a resurgence of interest due to the introduction of a number of new formulations of topical drugs and novel molecules. This has led to a plethora of new publications on management of cutaneous fungal disease. This paper summarizes the various clinical trial factors which may affect the published data regarding how well antifungal drugs work. Understanding these parameters allows the healthcare provider to choose more rationally between available agents based upon an assessment of the evidence.J Drugs Dermatol
. 2015;14(suppl 10):s48-s54.
While difficult to quantify precisely, dermatophyte infections are both common and widely distributed
worldwide.1-7 Estimates based upon epidemiologic
data from studies done in a variety of countries and continents suggest that some 20% to 25% of the world’s population
will be affected by superficial cutaneous fungal infections at least once during their lifetimes. Although fungal infections of the skin, hair, and nails can include those caused by candida species, the yeasts responsible for tinea versicolor, and nondermatophyte
molds, the vast majority of such infections are due to dermatophytic organisms.3,6 Thus, it is further estimated that 10% to 15% of the world’s population will acquire at least one dermatophytosis.6 In the United States, the most recent large scale investigation disclosed that, on average, over 4 million healthcare provider (HCP) visits directly related to cutaneous fungal infection occurred annually (range 3,583,590-6,754,460), the overwhelming majority due to dermatomycoses. This represented
some 0.4% of all ambulatory healthcare visits during the time period under study.5
It is worth suggesting that this situation will not likely abate in the near future. Well accepted predisposing factors are not likely
to decrease in either incidence or prevalence. Consider that onychomycosis is more prevalent among those with diabetes, peripheral vascular disease, and immunocompromise, and amongst the elderly.8,9 In fact, the changing demographic characteristics
of the population living in industrialized countries (mirrored in nations with emerging economies) includes: an increased
number of elderly, an increased prevalence of obesity, diabetes, and peripheral vascular disease, a longer survival of those with endogenous immunocompromised conditions, and the commonplace administration of iatrogenic immunosuppression
(including for solid organ transplantation). These factors may well lead to even more onychomycosis.10 Since onychomycosis is frequently associated with tinea pedis, and fungal infections of the foot are often felt to be responsible for dermatophytoses
of the groin and/or trunk,11 it is clear that such fungal infections are not going to diminish in the coming decades.
Moreover, in addition to the foregoing, social mores may lead to expansion of dermatophytoses. For example, earlier and more frequent participation in sports activities and the “workout”
craze among young adults could lead to more frequent micro-trauma to the nail unit and the pedal skin; and exposure to common public sports facilities (including showers and locker rooms) are also considered to predispose to onychomycosis.
12 Finally, virtually every factor enumerated above as having the potential to lead to a persistent epidemiologic onychomycosis
problem has also, independently, been implicated in the development of tinea pedis, an equally important reservoir
of pathogenic fungi.13
At present, there is little hope of eradicating dermatophytoses, as is the case with smallpox and nearly the case with polio. Faced with the inevitability of dermatophytosis, it is no wonder
that the HCP remains in search of simple, safe, convenient, and reliable therapies. That search has been further complicated
by the relatively recent development, approval, and marketing of newer antifungal agents. New formulations of pre-existing molecules (1% econazole nitrate foam and 2% naftifine
hydrochloride cream and gel) and novel molecules (10% efinaconazole solution, 1% luliconazole cream, 2% sertaconazole
nitrate cream, and 5% tavaborole solution) have recently appeared in the marketplace and re-awakened an interest in clinical mycology.
Should not picking the “best” agent for a given disease be as simple as going to the package insert of older and newer agents