What is the treatment for a viral infection affecting a child's fingernails?

Viral Infections Affecting Children's Fingernails

The most common viral infection affecting children's fingernails is hand, foot, and mouth disease (HFMD), which is self-limiting and requires only supportive care with focus on preventing transmission through good hygiene practices. 1

Primary Viral Nail Infections in Children

Hand, Foot, and Mouth Disease (HFMD)

• HFMD is caused by human enteroviruses and typically affects young children (average age 3.1 years) during late spring, summer, and fall months. 1
• The infection is usually mild and self-resolving, though rare neurologic or cardiopulmonary complications can occur. 1
• Diagnosis is clinical—no specific antiviral treatment exists, and management focuses on symptomatic relief and preventing spread. 1

Herpetic Whitlow

• Viral infections like herpetic whitlow can mimic bacterial abscesses but require non-operative treatment to prevent sequelae. 2
• A conservative approach is essential—surgical drainage is contraindicated in viral nail infections, unlike bacterial infections. 2

Critical Differential: Fungal vs. Viral Infection

If the nail shows thickening, discoloration, and friable texture, this suggests fungal onychomycosis rather than viral infection, and requires laboratory confirmation before treatment. 3

Diagnostic Approach for Suspected Fungal Infection

• Never diagnose fungal infection based on appearance alone—50% of dystrophic nails in children are non-fungal despite similar clinical presentation. 3
• Direct microscopy with potassium hydroxide (KOH) preparation and fungal culture on Sabouraud's glucose agar are essential for confirming diagnosis. 3
• Examine the child for concomitant tinea capitis and tinea pedis, and check parents and siblings for onychomycosis and tinea pedis, as household transmission is common. 4, 3

Treatment for Confirmed Fungal Onychomycosis

If laboratory testing confirms fungal infection:

• Terbinafine is the preferred first-line treatment for dermatophyte onychomycosis in children, with superior efficacy (88% cure rate). 4, 3

  • Weight-based dosing: <20 kg = 62.5 mg daily; 20-40 kg = 125 mg daily; >40 kg = 250 mg daily 4, 3
  • Duration: 6 weeks for fingernails, 12 weeks for toenails 4, 3

• Pulse itraconazole is equally effective (94-100% cure rates) and particularly useful when Candida species are suspected. 4, 3

  • Dosing: 5 mg/kg/day for 1 week per month 4, 3
  • Duration: 2 pulses (2 months) for fingernails, 3 pulses (3 months) for toenails 4, 3

• Pediatric studies demonstrate higher cure rates and faster response to treatment than in adults due to thinner, faster-growing nail plates. 4

Prevention and Infection Control

Good personal hygiene and implementation of surveillance systems are essential to stop disease spread and prevent outbreaks in childcare settings. 1

• HFMD spreads rapidly within childcare facilities (outbreak length 4-46 days), especially with delayed notification beyond 24 hours. 5
• Timely notification of clustered outbreaks (5 or more cases) to local health authorities within 24 hours is effective in minimizing incidence and outbreak length. 5
• Maintain short fingernails and scrub with soap and nailbrush when washing hands, as longer nails harbor greater microbial populations. 6

Common Pitfalls to Avoid

• Do not assume fungal infection without laboratory confirmation—bacterial infections (Green Nail Syndrome from Pseudomonas) and non-infectious causes (psoriasis, lichen planus, trauma) can mimic fungal infection. 3
• Do not surgically drain suspected viral infections like herpetic whitlow, as this worsens outcomes. 2
• Do not overlook examination of family members for fungal infections when onychomycosis is confirmed. 3