So-called nail fungus (onychomycosis) generally takes five forms:
- Proximal subungual onychomycosis
- Distal subungual onychomycosis
- Candidal onychomycosis
- White superficial onychomycosis
- Total dystrophic onychomycosis
Distal subungual onychomycosis
Affects the fingernails and toenails; usually caused by the pathogenic agent Trichophyton rubrum, it appears in the form of subungual hyperkeratosis (thickening of the skin), onycholysis (detachment of the nail plate) and yellowish striations in the centre of the nail plate. It is the most frequent form of nail fungus and is always associated with athlete’s foot. It often comes about due to factors of a hereditary nature.
White superficial onychomycosis
It mainly affects the toenails; caused by fungi (generally Trichophyton mentagrophytes) that colonise the surface of the body and the nails producing dull patches with white edges.
As the infection develops, the patches tend to join up until the whole surface of the nail is covered making it rough and fragile with the risk of crumbling. It is a type of mycosis that appears in about 10% of cases.
Proximal subungual onychomycosis
Affects the fingernails and toenails in equal measure; the pathogenic agent responsible is generally Trichophyton rubrum which appears by gradually invading the proximal nail fold (the area of skin that surrounds and covers the nail at the sides and in the proximal part), the nail matrix and subsequently also the nail plate. This rare form of mycosis unless properly treated can lead to total loss of the nail. It usually occurs in individuals with an immune deficiency, especially in HIV positive sufferers.
Pathologies associated with onychomycosis
Onychomycosis is very often associated with other pathologies of an infective type such as Tinea cruris (a mycotic infection of the groin), Tinea corporis (a skin mycosis that affects the parts of the body not covered by hair) and Tinea pedis, the pathology commonly known as athlete’s foot.