What causes peeling on a teen boy's fingers and toes?

Peeling Fingers and Toes in a Teen Boy

The most critical first step is to determine if this teen has had recent fever, as periungual peeling of fingers and toes 2-3 weeks after fever onset is a hallmark feature of Kawasaki disease, which requires urgent cardiac evaluation to prevent coronary artery complications. 1

Immediate Red Flag Assessment

If fever preceded the peeling by 2-3 weeks, evaluate urgently for Kawasaki disease:

• Desquamation of fingers and toes typically begins in the periungual region within 2-3 weeks after fever onset and may extend to palms and soles 1
• Look for history of high spiking fever (≥39°C) lasting ≥5 days 1
• Check for other principal features: conjunctival injection, oral changes (cracked lips, strawberry tongue), polymorphous rash, or cervical lymphadenopathy 1
• Obtain urgent echocardiogram if Kawasaki disease is suspected, as coronary artery disease can develop even with incomplete presentation 1

Common Non-Emergent Causes in Adolescents

Fungal Infection (Tinea Pedis/Manuum)

If no fever history and peeling is chronic/progressive:

• Fungal infections are among the most frequent causes, affecting approximately one-third of adults in industrialized countries 2
• Look for: thickening, discoloration, friable texture of nails; peeling between toes or on soles; asymmetric distribution 3, 4
• Never diagnose fungal infection based on appearance alone—50% of dystrophic nails are non-fungal despite similar presentation 5
• Confirm with potassium hydroxide (KOH) preparation and fungal culture on Sabouraud's glucose agar 3, 5
• Trichophyton rubrum is the most common causative agent 4, 2

Contact Dermatitis/Irritant Exposure

• Athletic shoe dermatitis is common in active adolescents 6
• Occupational or hobby-related chemical exposure (solvents, disinfectants) can cause peeling 1
• Hand eczema has strong hereditary component and presents with peeling, particularly in those with frequent water exposure 6

Palmoplantar Keratoderma

• Hyperkeratosis with subsequent peeling can occur in various conditions 1
• May be associated with friction, pressure, or underlying genetic conditions 1

Diagnostic Approach Algorithm

Step 1: Fever History

• Recent fever (within past 4 weeks)? → Evaluate for Kawasaki disease urgently 1
• No fever → Proceed to Step 2

Step 2: Distribution and Characteristics

• Periungual peeling only → Consider post-inflammatory causes, trauma, or early fungal infection 1, 3
• Interdigital involvement with maceration → Suspect tinea pedis (intertriginous type) 2
• Diffuse palmar/plantar involvement → Consider hyperkeratotic tinea, contact dermatitis, or keratoderma 1, 2
• Green/black nail discoloration → Pseudomonas infection (Green Nail Syndrome) 3, 5

Step 3: Laboratory Confirmation

• Obtain KOH preparation and fungal culture for any suspected fungal infection 3, 5
• Consider bacterial culture if green discoloration present 5

Treatment Based on Etiology

For Confirmed Fungal Infection:

• Localized involvement (<50% nail plate, <3 nails affected): Topical amorolfine 5% lacquer once-twice weekly for 6-12 months 1
• Extensive involvement (>50% nail plate or >3 nails): Oral terbinafine 250 mg daily for 6 weeks (fingernails) or 12 weeks (toenails) 5, 4
• Intertriginous tinea pedis: Topical azole or terbinafine twice daily for 4 weeks 7, 2

For Pseudomonas Infection:

• Keep affected area dry 3, 5
• Apply topical povidone-iodine 2% twice daily 3, 5

For Contact Dermatitis/Irritant Exposure:

• High-potency topical steroid twice daily 1
• Avoid mechanical stress (cushioned shoes, protective gloves) and chemical irritants 1
• Apply urea 10% cream three times daily for moisture barrier 1

Critical Pitfalls to Avoid

• Never dismiss peeling with recent fever history—Kawasaki disease can present with incomplete criteria and still cause coronary complications 1
• Do not treat presumed fungal infection without laboratory confirmation—this leads to unnecessary systemic antifungal exposure and delays correct diagnosis 5
• Avoid overlooking family members for fungal infections, as household transmission is common 5
• Do not ignore occupational/hobby exposures in adolescents—sports equipment, cleaning products, and athletic shoes are frequent culprits 1, 6