Physical Assessment Description of Toenail Fungus
When documenting toenail fungus on physical examination, describe the specific clinical pattern, nail changes, and associated findings to guide diagnosis and treatment.
Clinical Classification and Key Features
The physical assessment should identify one of five distinct clinical patterns, as each has diagnostic and therapeutic implications 1:
Distal and Lateral Subungual Onychomycosis (DLSO)
- Most common presentation (accounts for majority of cases), typically starting at the lateral edges of the hyponychium and spreading proximally 1
- Document subungual hyperkeratosis (thickening under the nail plate) and onycholysis (nail separation from the bed) 1, 2
- Note cream-colored discoloration progressing from distal/lateral edges toward the proximal nail fold 1
- Nail plate becomes friable and may break up, often related to trauma or keratolytic properties of dermatophytes 1
- Always examine surrounding skin for tinea pedis, which is nearly always present with toenail dermatophyte infection 1
- Describe whether infection is confined to one side or has spread to involve the entire nail bed 1
Superficial White Onychomycosis (SWO)
- Document white discoloration (not cream) on the surface of the nail plate 1, 3
- Note flaky, crumbling texture of the nail surface 1, 3
- Onycholysis is not typically present in this pattern 1
- Intercurrent foot infection is less frequent than in DLSO 1
Proximal Subungual Onychomycosis (PSO)
- Uncommon pattern that should raise suspicion for immunosuppression, HIV infection, peripheral vascular disease, or diabetes 1, 3
- Infection begins at the proximal nail fold and progresses distally 1
- Document absence or presence of paronychia 1
Total Dystrophic Onychomycosis (TDO)
- Represents advanced stage where the nail plate is almost completely destroyed 3
- Document extent of nail destruction and involvement 3
Candidal Onychomycosis
- Often presents with chronic paronychia (swelling of posterior nail fold) with secondary nail dystrophy 1
- Document detachment of cuticle from nail plate 1
- Note occupational history of wet work, particularly for fingernail involvement 1
Essential Physical Examination Elements
Nail-Specific Findings
- Thickening of the nail plate (measure if possible) 4, 5
- Discoloration (specify color: cream, white, yellow, green, or black) 4, 5
- Brittleness and texture changes 4
- Foul odor if present 4
- Onycholysis (nail separation) - document extent 1, 2
Associated Findings to Document
- Presence of tinea pedis on surrounding skin 1, 6
- Examine family members for onychomycosis and tinea pedis, as household transmission is common 6
- In children, check for tinea capitis and examine parents and siblings 6
Critical Documentation Pitfalls to Avoid
- Never diagnose based on appearance alone - 50% of nail dystrophy cases are non-fungal despite similar clinical presentation 6, 5
- Document that laboratory confirmation is pending or required, as treatment should not be instituted on clinical grounds alone 1
- Consider and document alternative diagnoses that can mimic fungal infection: psoriasis, lichen planus, trauma, and yellow nail syndrome 6, 3
- Note that bacterial infections (Pseudomonas causing green/black discoloration) require different management 6, 7
Recommended Documentation Template
Document the following systematically:
- Pattern: DLSO, SWO, PSO, TDO, or Candidal 1
- Location: Which toenails affected, unilateral vs bilateral 1
- Nail changes: Thickening, discoloration (specify color), brittleness, onycholysis (extent), hyperkeratosis 1, 4
- Associated findings: Tinea pedis present/absent, paronychia, odor 1, 4
- Percentage involvement: Document extent of nail involvement 8
- Plan: Specimens obtained for KOH preparation and fungal culture before treatment initiation 1, 5