What is the most likely diagnosis and recommended treatment for a fungal infection of the hands (tinea manuum)?

Fungal Infection of the Hands (Tinea Manuum)

Most Likely Diagnosis

Tinea manuum is a dermatophyte infection of the hands, most commonly caused by Trichophyton rubrum, presenting as an asymmetric, scaly eruption that may involve one or both hands. 1, 2

The infection typically manifests as:

• Erythematous, scaly patches with asymmetric distribution (a key diagnostic clue distinguishing fungal from other dermatoses) 1
• Possible annular (ring-shaped) morphology with central clearing 1
• Dry, hyperkeratotic scaling on palms and fingers, often resembling the "moccasin" pattern seen in tinea pedis 3
• May or may not be pruritic 1

Diagnostic Confirmation

Before initiating treatment, obtain skin scrapings from the active border of lesions for potassium hydroxide (KOH) microscopy and fungal culture to confirm the diagnosis. 1, 2

• KOH microscopy provides rapid preliminary diagnosis by visualizing fungal elements 1
• Culture on Sabouraud agar identifies the specific dermatophyte species 1
• Wood's lamp examination may provide additional diagnostic information 1, 2

Treatment Algorithm

For Limited Disease (Localized Involvement)

Start with topical antifungal therapy using an azole (clotrimazole, miconazole) or allylamine (terbinafine) agent applied twice daily for 2-4 weeks, continuing for at least one week after clinical clearing. 4, 2

• Topical allylamines require shorter treatment duration (1-2 weeks) compared to azoles (2-4 weeks) 4
• Address exacerbating factors such as excessive moisture and poor hygiene 4, 2
• If inflammation is prominent, consider a combination antifungal/corticosteroid preparation, but use cautiously due to risk of skin atrophy 4

For Extensive or Resistant Disease

If the infection covers an extensive area or fails to respond to topical therapy, switch to oral terbinafine 250 mg once daily for 2-4 weeks. 3

• Oral terbinafine demonstrated 86% mycological cure rate at 8 weeks with just 2 weeks of treatment for moccasin-type hand infections 3
• Alternative oral agents include itraconazole or griseofulvin if terbinafine is contraindicated 2
• Oral therapy is generally well-tolerated with minimal side effects 3

Critical Management Points

Treatment success requires:

• Compliance with the full treatment course, even after clinical improvement appears 2
• Good personal hygiene as an essential adjunct to antifungal therapy 4, 2
• Treatment continuation for at least one week after clinical clearing to prevent recurrence 4

Common Pitfalls to Avoid

• Do not diagnose based on appearance alone—asymmetry and annular morphology suggest fungal infection, but confirmation with KOH prep or culture is necessary before committing to prolonged therapy 1
• Do not stop treatment when lesions appear clinically clear—continue for at least one additional week to ensure mycological cure 4
• Do not use combination antifungal/steroid preparations for extended periods due to risk of skin atrophy and other steroid-related complications 4
• Do not ignore bilateral hand involvement or concurrent foot infection—tinea manuum often occurs with tinea pedis and both sites require treatment 3