What is the proper procedure for documenting toenail fungus?

Proper Documentation of Toenail Fungus

Proper documentation of toenail fungus requires laboratory confirmation through mycological testing before initiating treatment, as clinical features alone cannot reliably distinguish fungal nail infections from other nail disorders. 1

Diagnostic Process

Clinical Assessment

• Document specific clinical pattern of involvement:

  • Distal and Lateral Subungual Onychomycosis (DLSO): Most common form (majority of cases), affects hyponychium at lateral edges initially, spreads proximally, causes subungual hyperkeratosis and onycholysis 1
  • Superficial White Onychomycosis (SWO): Less common, affects nail plate surface with white discoloration and flaky appearance 1
  • Proximal Subungual Onychomycosis (PSO): Uncommon, often associated with immunosuppression, peripheral vascular disease, or diabetes 1
  • Total Dystrophic Onychomycosis: Advanced stage with complete nail destruction 1

• Document specific nail characteristics:

  • Color changes (cream, white, green, or black discoloration)
  • Texture changes (thickened, brittle, soft, friable)
  • Structural changes (onycholysis, subungual hyperkeratosis)
  • Presence of dermatophytoma (dense white lesion beneath nail) 1
  • Nail thickness (measure if >2mm, as this affects treatment prognosis) 1

Laboratory Confirmation

Laboratory confirmation is essential as 50% of nail dystrophies are non-fungal in origin 1. Document:

1. Direct microscopic examination:

   • KOH preparation or preferably calcofluor white staining (higher sensitivity) 2
   • Document presence/absence of fungal elements 1

2. Fungal culture:

   • Takes 2-6 weeks for results 1
   • Document specific pathogen identified (dermatophyte, non-dermatophyte mold, or yeast) 1
   • Most common causative organisms: Trichophyton rubrum (most common), Trichophyton mentagrophytes 3

3. Molecular diagnostics (if available):

   • PCR testing offers faster turnaround (<2 days) and higher detection rates 1
   • Document results and specific pathogens identified 1

Proper Specimen Collection

For accurate diagnosis, document proper specimen collection technique:

• Material taken from discolored, dystrophic, or brittle parts of the nail 1
• Affected nail cut as far back as possible through entire thickness 1
• Include crumbly material from under the nail 1
• For SWO, nail scrapings taken with curette 1
• If associated skin lesions present, samples from these should also be collected 1

Differential Diagnosis Documentation

Document consideration and exclusion of conditions that mimic onychomycosis:

• Psoriasis
• Chronic trauma
• Lichen planus
• Bacterial infection (especially Pseudomonas with green/black discoloration)
• Onychogryphosis
• Subungual malignant melanoma
• Yellow nail syndrome
• Darier disease 1, 2

Treatment Documentation

When documenting treatment plans, include:

1. Treatment selection rationale:

   • Severity of infection (% of nail involvement)
   • Location (fingernail vs. toenail)
   • Causative organism
   • Patient comorbidities
   • Previous treatment history 3

2. For oral treatments:

   • Terbinafine: 250mg daily for 6 weeks (fingernails) or 12 weeks (toenails) 3
   • Document baseline liver function tests and complete blood count 1

3. For topical treatments:

   • Application frequency and duration
   • Adjunctive nail debridement procedures 2

4. Expected outcomes:

   • Document that clinical improvement may lag behind mycological cure
   • Complete nail regrowth takes 6-12 months 2
   • Document potential for recurrence (approximately 15%) 3

Common Pitfalls to Avoid

• Avoid treating without mycological confirmation: The British Journal of Dermatology strongly recommends against initiating treatment based on clinical appearance alone 1
• Avoid misidentifying contaminants as pathogens: Non-dermatophyte molds are often contaminants rather than causative agents 1
• Document nail thickness: Nails >2mm thick have poorer treatment outcomes 1
• Document presence of dermatophytoma: These dense white lesions beneath the nail can be resistant to antifungal treatment without prior removal 1
• Document associated conditions: PSO may indicate immunosuppression, peripheral vascular disease, or diabetes 1

By following this comprehensive documentation approach, clinicians can accurately diagnose toenail fungus, select appropriate treatment, and monitor outcomes effectively.