What are the management options for an adult with big toe nail pain after nail regrowth, possibly due to fungal infection or ingrown toenail?

Management of Big Toe Nail Pain After Regrowth

First, determine if this is an ingrown toenail (onychocryptosis) versus fungal infection (onychomycosis), as these require completely different treatment approaches and ingrown nails cause significantly more acute pain and morbidity.

Initial Diagnostic Approach

Key Clinical Features to Distinguish the Cause

For Ingrown Toenail:

• Pain with pressure on or movement of the nail 1
• Periungual skin that is swollen, erythematous, and painful 1
• Lateral or medial nail edge embedded in the nail fold 2
• Acute onset of symptoms after nail regrowth 3
• Most common in the great toe (hallux) 2, 3

For Fungal Infection (Onychomycosis):

• Nail becomes thickened, discolored, and friable but typically less acutely painful 1
• Gradual onset over weeks to months 1
• Unlike dermatophyte infections, Candida infections cause pain with pressure and movement, but also present with proximal nail fold involvement (paronychia) 1
• Subungual hyperkeratosis and onycholysis 1

Critical Pitfall: Many noninfectious conditions mimic onychomycosis including chronic trauma, psoriasis, and lichen planus, but the nail surface does not usually become soft and friable as in fungal infection 1. If fungal infection is suspected, obtain laboratory confirmation before starting antifungal therapy 4.

Management Algorithm

If Ingrown Toenail (Onychocryptosis) is Diagnosed:

For Mild to Moderate Cases (First-Line):

• Correct inappropriate footwear immediately 2
• Soak the affected toe followed by applying mid- to high-potency topical steroid 2
• Place wisps of cotton or dental floss under the ingrown lateral nail edge 2
• Apply a gutter splint to the ingrown nail edge to separate it from the lateral fold for immediate pain relief 2
• Consider cotton nail cast made from cotton and cyanoacrylate adhesive or taping the lateral nail fold 2

For Moderate to Severe Cases or Failed Conservative Treatment:

• Surgical approaches are superior to nonsurgical ones for preventing recurrence 2
• Partial avulsion of the lateral edge of the nail plate is the most common surgical approach 2
• Matrixectomy (surgical, chemical, or electrosurgical) further prevents recurrence 2
• These surgical approaches eliminate the interaction between the nail plate and nail fold to stop local trauma and inflammatory reaction 2

If Onychomycosis is Suspected:

Mandatory Pre-Treatment Step:

• Obtain confirmatory testing (KOH microscopy, fungal culture, histopathology, or PCR) before initiating any antifungal therapy 4
• Good nail specimens are crucial: cut the affected nail as far back as possible through the entire thickness, including any crumbly material 1

Treatment Based on Disease Severity:

For Mild Disease (Topical Therapy):

• Topical antifungals are limited to superficial white onychomycosis or early distal lateral subungual onychomycosis when <80% of nail plate is affected with no lunula involvement 1
• Amorolfine 5% lacquer applied once or twice weekly for 6-12 months after gentle filing of diseased nail areas, with approximately 50% efficacy 1
• Critical limitation: Drug concentration drops by 1000 times from outer to inner nail surface, limiting topical efficacy 1

For Moderate to Severe Disease (Systemic Therapy - First-Line):

• Oral terbinafine 250 mg daily for 12 weeks is the first-line systemic therapy for toenail onychomycosis 5
• Obtain baseline liver function tests and complete blood count before initiating terbinafine 5
• Oral antifungals have higher cure rates than topical agents 4

Prevention of Recurrence:

• Discard old contaminated footwear or decontaminate with naphthalene mothballs 5
• Apply antifungal powders inside shoes regularly 5
• Wear cotton, absorbent socks and change daily 5
• Keep toenails trimmed short and avoid sharing nail clippers 5
• Wear protective footwear in public bathing facilities, gyms, and hotel rooms 5

Special Considerations

If Candida Paronychia is Present:

• Look for proximal nail fold involvement with swelling, erythema, and pain 1
• More common in individuals with occupations requiring repeated hand immersion in water 1
• Bacterial superinfection is common and may require separate treatment 1

Important Caveat: Onychomycosis is a chronic disease with high recurrence rates, requiring long-term prevention strategies even after successful treatment 4. Treatment may take 6-12 months for complete resolution 1.