Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Eirini E. Merika and L. Claire Fuller
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Superficial fungal infections are the commonest of all mucocutaneous infections and appear to be on the increase. Dermatophytes infect keratinized epithelium, the hair and nails. Tinea pedis (athlete’s foot) describes a dermatophyte infection of the soles of the feet and interdigital spaces; tinea cruris, an infection of the groin; tinea facei, the face; and tinea corporis the rest of the skin.
Vena GA, Chieco P, Posa F, Garofalo A, Bosco A, Cassano N. New Microbiol 2012; 35: 207–13.
A retrospective analysis involving 6133 patients with 20.4% suffering with tinea pedis with a male predominance showing that over the last decades tinea pedis has becoming increasingly common.
Skin dermatophytosis rarely causes significant morbidity and certainly not mortality, but there is some evidence that, especially tinea pedis, it acts as a portal of entry for bacteria that produce impetiginization, lymphangitis, and bacterial cellulitis.
Topical antifungal treatment (with topical azoles or allylamines) of tinea pedis is generally adequate, as it is for small areas of tinea corporis and cruris, but for extensive infections, and especially those in immunosuppressed patients, oral therapy may be required. Several antifungal topical therapies are available without prescription, and the vast majority of the disease burden is likely to be managed without intervention from medical personnel. Treatment schedules vary but it is generally accepted that treatment should be applied once to twice daily for 2 to 4 weeks, continuing for at least 1 week after the lesions have cleared. Eradication of tinea elsewhere in the body, such as tinea pedis in the context of tinea cruris or tinea ungium in tinea pedis, is paramount for effective treatment and prevention of relapse.
Extensive forms of infection, failure of local treatment or relapse from inadequate therapy may require oral therapy with systemic antifungals such as terbinafine, fluconazole or itraconazole. Oral therapy remains the most effective agent against extensive or non-responsive forms of tinea. British prescribing guidelines suggest the following regimens: terbinafine 250 mg daily for 14 days, fluconazole 50 mg daily for 2 to 4 weeks (up to 6 weeks in tinea pedis), and itraconazole 100 mg daily for 15 days or 200 mg daily for 7 days (longer for tinea pedis and manuum). Severe macerated forms of tinea pedis may well be superinfected with bacteria justifying concomitant antibiotic therapy, although some topical antifungal agents have in vitro antibacterial activity, e.g., ciclopiroxolamine. Other than general hygiene, there is only anecdotal evidence to support prevention strategies to minimize re-infection, such as using antifungal powder to areas prone to fungal infections after showering, and wearing shower shoes in public bathing facilities.
Roujeau JC, Sigurgeirsson B, Korting HC, Kerl H, Paul C. Dermatology 2004; 209: 301–7.
Two hundred and forty-three patients with acute bacterial cellulitis and 467 age- and gender-matched controls were investigated, and mycology-proven tinea pedis was shown to be a significant risk factor for cellulitis (odds ratio [OR] 2.4; p<0.001). Interdigital tinea pedis conferred the highest risk (OR 3.2, p<0.001) followed by onychomycosis (OR 2.2, p<0.001) and then plantar-type tinea pedis (OR 1.2, p=0.005). A previous history of cellulitis, venous insufficiency, and leg edema was also reported to increase the risk.
Skin scrapings for mycological microscopy and culture
Skin swabs for bacteriology
The lesions should be scraped carefully, harvesting surface scale with a no. 15 blade or banana-shaped knife. The active edges of large lesions are likely to yield more scale. Avoiding the application of emollients prior to sampling aids sample collection and analysis. Blister and pustule tops may be ruptured and the contents swabbed and placed directly onto agar plates.
Marks R, Dykes P, Motley R. London: Taylor & Francis, 1993.
The principal organisms responsible for tinea pedis are Trichophyton rubrum, T. mentagrophytes and Epidermophyton floccosum. Not all scaly eruptions are due to tinea, so confirming the presence of a dermatophyte enables the instigation of relevant, targeted therapy and avoids causing unwanted side effects in non-fungal causes.
Havlickova B, Czaika VA, Friedrich M. Mycoses 2008; 51(Suppl 4): 2–15.
Trichophyton, Microsporum and Epidermophyton are the pathogens responsible for most skin dermatophytoses with considerably variable incidence globally mainly due to local socio-economic conditions and cultural practices. There seems to be a predominance of tinea pedis in developed countries with Trichophyton rubrum the leading pathogen.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
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