ONYCHOMYCOSIS

'Onychomycosis' means fungal infection of the nails. It represents up to 20% of all nail disorders.
This condition may affect toe- or fingernails, but toenail infections are particularly common. The prevalence of onychomycosis is about 6-8% in the adult population.^[1] The most common type of onychomycosis (80-90%), caused by dermatophytes, is technically known as tinea unguium (tinea of the nails).^[2]

Contents

Symptoms

Causes

Treatment

Natural remedies

Relative effectiveness of treatments

New developments

References

See also

External Links

Symptoms

The nail plate can have a thickened, yellow, or cloudy appearance. The nails can become rough and crumbly, or can separate from the nail bed. There is usually no pain or other bodily symptoms, unless the disease is severe. ^[3]

Causes

Dermatophytes are the fungi most commonly responsible for onychomycosis. Two dermatophyte species, ''Trichophyton rubrum'' and ''Trichophyton interdigitale'', cause the vast majority of onychomycosis cases worldwide. Other related dermatophyte fungi that may be involved are ''Epidermophyton floccosum'', ''Trichophyton violaceum'', ''Microsporum gypseum'', ''Trichophyton tonsurans'', ''Trichophyton soudanense'' (considered by some to be an African variant of ''T. rubrum'' rather than a full-fledged separate species) and the cattle ringworm fungus ''Trichophyton verrucosum''. A common outdated name that may still be reported by medical laboratories is ''Trichophyton mentagrophytes'' for ''T. interdigitale''. The name ''T. mentagrophytes'' is now restricted to the agent of favus skin infection of the mouse; though this fungus may be transmitted from mice and their danders to humans, it generally infects skin and not nails.
Other causal fungi include yeasts (5-17%), ''e.g.'', ''Candida'', and non-dermatophytic moulds, in particular members of the mould genera ''Scytalidium'' (name recently changed to ''Neoscytalidium''), ''Scopulariopsis'', and ''Aspergillus''.

Yeasts mainly cause fingernail onychomycosis in people whose hands are often submerged in water. ''Scytalidium'' mainly affects people in the tropics, though it persists if they later move to areas of temperate climate.
Other moulds mainly affect people over the age of 60, and their presence in the nail reflects a slight weakening in the nail's ability to defend itself against fungal invasion.

Treatment

Treatments are usually commenced after laboratory confirmation of fungal invasion based on microscopic examination and culture of nail scrapings or clippings. Systemic antifungal medications such as terbinafine and itraconazole have been shown to be effective in treating it, as have some topical nail paints, such as one containing ciclopirox.

Natural remedies

As with many diseases, there are also some scientifically unverified folk or alternative medicine remedies.

★ Grapefruit seed extract as a natural antimicrobial is not demonstrated. Its effectiveness is scientifically unverified. Multiple studies indicate that the universal antimicrobial activity is due to contamination with synthetic preservatives that were unlikely to be made from the seeds of the grapefruit.^{[4][5][6][7][8]}

★ Distilled white vinegar. Drops are applied to the cuticle twice a day. This method does not kill the fungus, but the vinegar allegedly changes the pH (acid content) of the new nail formed in that 12-hour period. (The scientific perspective, however, is that vinegar is unlikely to penetrate the dense keratinous tissue thoroughly enough to have any significant effect. Instead, it may be absorbed by the skin above the nail and work its way to where the nail is actually forming.) As the old, infected nail grows and is cut away, it is said to be replaced by an acidic nail, uninhabitable by fungi. Several months of consistent application are involved.

Relative effectiveness of treatments

A 2000 study assessed the effects of different topical treatments for fungal infections of the skin and nails of the foot.^[9]
The study reviewed 72 randomized clinical trials dating up to December 1997. The main findings were:

★ allylamines, azoles and undecenoic acid were efficacious.

★ allylamines cured slightly more infections than azoles, but were much more expensive.

★ the most cost-effective strategy was first to treat with azoles or undecenoic acid, and to use allylamines only if that failed.
A 2002 study compared the efficacy and safety of terbinafine in comparison with placebo, itraconazole and griseofulvin in treating fungal infections of the nails.^[10] The main findings were that for reduced fungus terbinafine was found to be significantly better than itraconazole and griseofulvin, and terbinafine was better tolerated than itraconazole.

★ A small study in 2004 showed that ciclopirox nail paint was more effective when combined with topical urea cream.^[11]

★ A study of 504 patients in 2007 found that aggressive debridement of the nail combined with oral terbafine significantly reduced symptom frequency over terbafine alone.^[12]

★ A 2007 randomised clinical trial with 249 patients show that a combination of amorolfine nail lacquer and oral terbinafine enhances clinical efficacy and is more cost-effective than terbinafine alone.^[13]

New developments

★ A medicinal nail lacquer, NM100060 from NexMed is in Phase III clinical trials^[14]. It contains terbinafine as the active ingredient and a permeation enhancer which facilitates the delivery of the drug into the nail bed where the fungus resides. Commercial sale of the product is expected to begin no earlier than in 2008. ^[15]
Clinical trials investigating Onychomycosis: [2].

References

1. Impact 07 - Dermatology
2. Prevalence and risk factors of tinea unguium and tinea pedis in the general population in Spain, Perea S, Ramos MJ, Garau M, Gonzalez A, Noriega AR, del Palacio A, , , J. Clin. Microbiol., 2000
3. http://www.emedicine.com/derm/topic300.htm
4. Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained, von Woedtke T, Schlüter B, Pflegel P, Lindequist U, Jülich WD, , , Pharmazie, 1999
5. [Analysis of components in natural food additive "grapefruit seed extract" by HPLC and LC/MS], Sakamoto S, Sato K, Maitani T, Yamada T, , , Eisei Shikenjo hōkoku. Bulletin of National Institute of Hygienic Sciences, 1996
6. Identification of benzethonium chloride in commercial grapefruit seed extracts, Takeoka G, Dao L, Wong RY, Lundin R, Mahoney N, , , J. Agric. Food Chem., 2001
7. Identification of benzalkonium chloride in commercial grapefruit seed extracts, Takeoka GR, Dao LT, Wong RY, Harden LA, , , J. Agric. Food Chem., 2005
8. Development and validation of an HPLC/UV/MS method for simultaneous determination of 18 preservatives in grapefruit seed extract, Ganzera M, Aberham A, Stuppner H, , , J. Agric. Food Chem., 2006
9. Topical treatments for fungal infections of the skin and nails of the foot, Crawford F, Hart R, Bell-Syer S, Torgerson D, Young P, Russell I, , , Cochrane database of systematic reviews (Online), 2000
10. Terbinafine in fungal infections of the nails: a meta-analysis of randomized clinical trials, Haugh M, Helou S, Boissel JP, Cribier BJ, , , Br. J. Dermatol., 2002
11. Boosts drug entry into nails: urea, ciclopirox combo tested for onychomycosis.(Focus on Skin Disorders)
12. The impact of aggressive debridement used as an adjunct therapy with terbinafine on perceptions of patients undergoing treatment for toenail onychomycosis, Potter LP, Mathias SD, Raut M, Kianifard F, Landsman A, Tavakkol A, , , The Journal of dermatological treatment, 2007
13. A multicentre, randomized, controlled study of the efficacy, safety and cost-effectiveness of a combination therapy with amorolfine nail lacquer and oral terbinafine compared with oral terbinafine alone for the treatment of onychomycosis with matrix involvement, Baran R, Sigurgeirsson B, Berker DD, ''et al'', , , , 2007
14.
15. [1]

See also

★ Nail disease

★ List of tinea infections

External Links

★ Fungal Nail Infections ('Onychomycosis')

★ Onychomycosis