Onychomycosis represents 50% of all nail disease (Elewski, 1996) and the most difficult to treat of all skin mycoses. Fungal infections of the toenails are almost always caused by a dermatophyte fungi, with distal and lateral subungual onychomycosis being the most common (Roberts, 1993). These molds, and occasionally yeast, infect an already diseased or traumatized nail. Arterial circulatory disorders, peripheral nerve disease, disturbances of the venous and lymphatic drainage systems, as well as chronic paronychia are common predisposing factors (Haneke, 1991). Onychomycosis may cause disturbances in nail growth with loosening or separation of all or part of the nail plate from the nail bed at the free edge (Helfand, 1989). Anti-fungal drug treatments remain difficult to enact because predisposing factors are usually not amenable to therapy. Patience combined with optimal patient compliance are mediators. A high recurrence rate is estimated at 80 - 90% (Haneke, 1991).
It has been estimated, that fungal (onychomycosis) infections explain 50% of all nail diseases. Types of fungal infections are differentiated by causative pathogen and the method of fungal invasion into the nail plate. The literature supports that distal subungual onychomycosis is the most common form of fungus (typically Tricholphyton rubrum) invading the distal nail plate and hyponychium (Elewski, 1996;Scher, 1983; Hobday, 1995; Tierney, McPhee & Papadakis, 1997; Berg, Cantwell, Heudebert, & Sebastian, 1993). Trauma to nails plays an important role as a precursor to onychomycosis. Dermatophytes, yeasts, and non-dermatophytes molds are the three major groups of fungi that can cause onychomycosis (Hobday, 1995; Elewski, 1996).
Onychomycosis can be visible by changes in the texture, structure, and presentation of one, several, or all nails of the upper and lower extremities. Typically, the nail plate becomes thick and discolored (onychauxis) and the damaged nail becomes brittle, crumbly, and a subungual hyperkeratosis is present with an uplifting of the nail plate (onycholysis). Generally, subungual hyperkeratosis (onycholysis) may be regarded as the most reliable sign of onychomycosis (Scher, 1983). A 'musty' odor may also accompany these findings.
Occasionally, the surrounding skin, proximal nail fold, near the fungal nail may be involved (Hobday, 1995). The proximal nail fold and the two lateral fold makeup the three borders the nail plate. The raised portion of the proximal nail fold is the cuticle. Paronychia is acute pain and swelling associated with a past trauma to the nail, poor nail care, fungal infection (onychomycosis) or an 'in-grown nail' (onychocryptosis) around the lateral nail fold (Berg, Cantwell, Heudebert, & Sebastian, 1993).
Grossly elongated nails (onychogryphosis) may be a result of poor hygiene or neglect in foot care. Onychogryphosis may result in extreme curvature with a 'hooked' configuration (gryphos, meaning "claw") to the nail (Omura & Rye, 1994).
Subungual hematoma can be defined as trauma resulting in the collection of reddish-blue blood in the nail bed. Increased pressure, under the nail plate, causes extreme tenderness on palpation (Berg, Cantwell, Heudebert, & Sebastian, 1993).
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