Nails, fungal infections

Onychomycosis, fungal infections involving the nails, requires oral antifungal therapy. Topical agents do not adequately penetrate the nail. 

Tinea infections are superficial fungal infections in which the pathogen remains within the keratinous layers of the skin or nails. Typically these infections are named for the affected body part, such as tinea pedis (feet), tinea cruris (groin), and tinea corporis (body). Tinea infections are commonly referred to as ringworm due to the characteristic circular lesions. In actuality, tinea lesions can vary from rings to scales and single or multiple lesions. 

Gupta AK, Cooper EA, Ryder JE, et al. Optimal management of fungal infections of the skin, hair, and nails. Am J Clin Dermatol 2004 5 225-237. 

The most widespread are dermatophytic fungal infections, which include skin, hair, and nails. Most infections can be cured by using topical drugs, such as tolnaftate, undecylenic acid, haloprogin, clotrimazole, and miconazole. Griseofulvin is used orally for deep infections, in particular for infections of the nail bed. Currently, ketoconazole is widely used for treating chronic dermatophytes. 

Over the last fifty years, as chemotherapeutics for the treatment of cancer, bacterial infections, and to prevent transplant rejections have improved, there has been a concomitant increase in the number of patients suffering from fungal infections. In the past, most fungal infections were superficial, affecting only the skin, hair, or nails. However, as medical science has progressed in other disease areas, many more patients are immunocompromised, which has resulted in a greater incidence of systemic fungal infections. 

Itraconazole (Sporanox), a triazole, is highly lipophilic and concentrates in skin. It is approved for both cutaneous deep fungal infections and dermatophyte nail disease, for which shorter courses of therapy are probably effective. Pulse therapy, whereby the drug is administered for 1 week and then the patient is off treatment for 3 weeks between pulses, may reduce toxicity without compromising antifungal efficacy. 

Superficial fungal infections involve cutaneous surfaces, such as the skin, nails, and hair, and mucous membrane surfaces, such as the oropharynx and vagina. A growing number of topical and systemic agents are available for the treatment of these infections. Deep-... 

Nonprescription topical antifungal agent not effective in the treatment of deeper fungal infections of the skin, nor is it reliable in the treatment of fungal infections involving the scalp or nail beds Candida is resistant useful for patients desiring self-medication of mild tinea infections patients must be advised of limitations... 

It is indicated in fungal infections of skin, scalp and nails, tinea of hand and beard and athlete s foot. 

Suhonen, R. E., Dawber, R. P. R., and Ellis, D. H. (1999). Fungal Infections of the Skin, Hair and Nails. London Martin Dunitz. 

Fungal infections superficial dermatophyte or Candida infections purely involving the skin can be treated with a topical imidazole (e.g. clotrimazole, miconazole). Pityriasis versicolor, a yeast infection, primarily involves the trunk m young adults it responds poorly to imidazoles but topical terbinafine or selenium sulphide preparations are effective severe infection may require systemic itraconazole. Invasion of hair or nails by a dermatophyte or a deep mycosis requires systemic therapy terbinafine is the most effective drug. Terbinafine and griseo-fulvin are ineffective against yeasts, for which itraconazole is an alternative. Itraconazole can be used in weekly pulses each month for 3-4 months it is less effective against dermatophytes than terbinafine. 

Dermatophyte is the term applied to a range of fungi capable of colonizing the skin, nails or hair. The principal dermatophytic fungi are Trichophyton, Microsporum and Epidermophyton species. The most commonly encountered dermatophytic infections are athlete s foot (infection of the foot) and ringworm (fungal infection of the scalp or skin). 

Fungal infections are divided into superficial or deep-seated infections. Superficial infections affect the skin, nails or mucosal surfaces of the mouth or genital tract. In contrast, deep-seated fungal diseases may target the lung or disseminate via the bloodstream to organs such as the brain, spleen, liver or skeletal system. 

The fungal infections of the skin and nails include Tinea pedis (athlete s foot), T. capitis and T. 

Indications Fungal infections of the skin and nails Category Antimycobacterial Half-life 22-26 hours... 

Athlete s foot is the commonest of a group of topical fungal infections (see Chapter 28) caused by dermatophytes, organisms that invade and proliferate on the outermost horny layer (stratum corneum) of the skin, hair and nails. They do not normally penetrate deeper into the skin or tissues. Dermatophytes tend to thrive in areas of the body that are occluded and moist. 

Onychomycosis is one of the most difficult fungal infections to treat because of the time it takes for the nail to grow, the hardness of the nail plate and location of the infectious process (between the nail bed and plate). 

Haugh M, Helou S, Boissel JP, Cribier BJ. Terbinafine in fungal infections of flie nails A meta-analysis of randomized clinical trials. Br J Dermatol 2002 147 118-121. 

For example, griseofulvin has an affinity for keratin. Since this drug can be used to treat fungal infections of the skin and nails its sequestration into keratin is something of an advantage. 

Organisms called dermatophytes cause the majority of superficial fungal infections of the skin, hair and nails. The most common dermatophytes that infect humans belong to... 

Superficial fungal infections can usually be treated with topical preparations, but systemic antifungal drugs can be necessary for nail and scalp infections, or if skin infection is extensive and unresponsive to topical therapy. 

Drugs used to treat fungal infection of the skin and nails... 

Mr Jacobson is a widower of 64, who lives alone. This patient has serious fungal infection of most of his toenails. The use of topical antifungals has not resolved the problem - probably because of poor compliance by the patient. Mr Jacobson is reluctant to consider total nail avulsion and so are you now because the infection has spread to so many toenails. You decide to refer the patient to his GP. You tell Mr Jacobson you will write to his GP and your recommendation is oral therapy with fluconazole. 

Some of these drugs (for example ketoconazole and fluconazole) are used orally to treat systemic fungal infections others (for example econazole and tioconazole) are used topically to treat skin and nail infection. 

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