Tinea unguium

• Meissner, 1853
• Virchow, 1854

Onychomycosis, nail mycosis, nail fungus.

• Fungal infection of the nails
• If the nail is infected with dermatophytes alone, it is called "tinea unguium". If yeasts or moulds infect the nail (or in the case of a mixed infection), it is an "onychomycosis"

Division

• Distal subungual onychomycosis (DSOM): most common type.
• Proximal subungual type (PSOM).
• White superficial onychomycosis (WOOM).
• Onychomycosis due to moulds.
• Onychomycosis due to Candida (Paronychia candidamycetica).
• Total dystrophic onychomycosis.
• Leukonychia trichophytica: whitish, superficial onychomycosis (usually caused by tryichophytes).
• Dystrophic onychomycosis: classic form seen in chronic mucocutaneous candidiasis.
• Onychia et Paronychia candidosa: usually caused by Candida albicans and is associated with chronic inflammation of the proximal and lateral nail wall. Discolouration and transverse grooves are seen

"Immune phenomena in dermatophytoses

• When the human organism is attacked by dermatophytes, antibodies are formed in the skin. This can be detected by means of intradermal testing.
• A type I or type IV reaction may occur after injection of (trichophytin)

• Incidence (Europe/USA): approx. 20%
• Incidence (Europe/USA) > 65 y.: up to 45%

• Exciter
  • Approximately 99% of all fungal nail infections are dermatophytes
  • Mostly:
    • Trichophyton rubrum (dermatophyte)
    • Trichophyton mentagrophytes (dermatophyte)
    • Candida albicans (yeast)
    • Candida tropicalis (yeast)
    • Scopulariopsis brevicaulis (mould)
    • Aspergillus niger (mould)
    • Hendersonula toruloidea (mould)

• In most cases, tinea pedis already exists. The pathogens enter the nail bed via the hyponychium
• In bakers, onychomycosis due to Candida may occur more frequently than in the normal population. The increased moisture work and nutrient supply provide a suitable environment for yeast fungi
• The toenails are affected significantly more often than the fingernails
• Predisposing factors
  • Trauma (CAVE too tight/short shoes)
  • Anatomical anomalies
  • ↓ Blood circulation (articular, venous)
  • Disorders of lymphatic drainage
  • Neuropathies
  • Diabetes mellitus
  • Immune suppression
  • Tinea pedum

• After the fungi have invaded the nail bed via the hyponychium, the subungunal hyperkeratosis causes the nail plate to detach (onycholysis semilunaris)
• A yellow discolouration is called "dyschromasia"
• The term "green nail syndrome" is used for secondary infestation with Pseudomonas aeruginosa
• ↑ subungual keratosis à crumb nails (onychodystrophy)

• Nail material removal:
• Disinfection with 70% alcohol
• As proximal as possible!
• Curettage technique
• Native and culture!
• Histological examination!

In case of pos. findings for moulds:

• Repeat 3 times (only if no dermatophytes can be detected 3 times is onychomycosis due to moulds to be assumed)

• Success rate: 50%
• Recurrence rates: 5%-20% or 40% (grisefulvin)

• Old patients (and those with PAOD) may experience slowed nail growth, so the appropriateness of systemic therapy must be considered

• Improve blood circulation (abstinence from nicotine)
• No constricting footwear
• No air-impermeable shoes
• Disinfection of footwear
• Avoid moisture
• Dry hands and feet thoroughly
• Change clothes frequently
• Boil socks at 95 °C, if possible

Topical therapy

• Indication
  • distal onychomycosis
  • DSO < 50% of nail plate affected
  • DSO ≤ 2 nails affected

• Roughen the nail plate (with nail files)/grind it down
  • Alternatively: removal of the diseased nail plate (→ ↓fungal volume, ↑active substance penetration)
  • Surgically (by podiatrists) or chemically (40% urea paste NRF 5.11-650)

• Subsequently use an antifungal nail varnish
  • Ciclopirox nail varnish 2x/week for 6-12 mon
  • Amorolfin- nail varnish 2x/week for 6-12 mon.

Systhem therapy

• Indication:
  • DSO > 50% involvement of the nail plate or nail matrix
  • DSO ≥ 3 nails
  • Deep WOOM
  • Proximal subungual onychomycosis (PSO)
• Terbinafine (Tbl.) p.o. 250 mg 1x tgl. for months or 250 mg 1x tgl. for 1 week, then 250 mg 1x weekly (regimen according to Tietz). Always use until healing. Ind: T. rubrum, T. interdigitale, T. mentagrophytes, S. brevicaulis
• Itraconazole p.o. 400 mg 1x weekly, followed by a therapy break of 3 weeks. Repeat the cycle 2x (3 cycles in total) or 400 mg 1x tgl. for 1 week, then 1x weekly (scheme according to Tietz). Always use until healing. Ind: T. rubrum, C. albicans, S. brevicaulis.
• Fluconazole p.o. 150 mg 1x weekly or 150 mg 1x tgl. for 7 days, then 1x weekly (regimen according to Tietz). Always use until healing. Ind: T. rubrum, C. albicans, M. canis.

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