How do I differentiate and treat a corn versus a wart?

Differentiating Corn vs Wart

The definitive diagnostic test is paring down the lesion with a scalpel: warts will show pinpoint bleeding from exposed capillary loops of elongated dermal papillae, while corns and calluses will not bleed and reveal a translucent central core or homogenous thickened keratin. 1

Clinical Differentiation

Key Diagnostic Features

Warts (Verruca):

• Paring reveals pinpoint bleeding as capillary loops are exposed—this is pathognomonic 1
• Disrupted or absent skin lines across the lesion 2
• May appear as hyperkeratotic papulonodules 2
• Caused by HPV infection (types 1,2,4,27, or 57 for common warts) 1

Corns (Heloma Durum):

• Paring reveals a translucent central core without bleeding 1
• Hard, conical plug of keratin pointing toward underlying bone 3
• Located at pressure points, typically over bony prominences 3
• Preserved skin lines may be visible 2

Calluses (Tyloma):

• Paring shows homogenous thickened keratin without bleeding 1
• Diffuse, yellowish thickening at pressure areas 1, 2
• Skin lines remain intact 2

Examination Technique

1. Soak the lesion in warm water to soften tissue 2
2. Pare down carefully with a scalpel blade, removing superficial layers 1
3. Inspect closely for bleeding points (wart) versus translucent core (corn) versus uniform opacity (callus) 1

Critical Pitfall

Do not confuse inflamed warts (which appear red) with corns—both can look similar, making paring essential for accurate diagnosis 1. In immunosuppressed patients, consider biopsy if warts are unusually extensive or treatment-resistant, as this may indicate underlying immune deficit or rarely squamous cell carcinoma 1

Treatment Approach

For Warts

First-line treatment options:

• Salicylic acid 15-40% topical paints or ointments (Level of evidence 1+, Strength A) 1

  • Apply after paring/abrading the wart
  • Use daily with occlusion when possible
  • Continue for up to 3-4 months 1

• Cryotherapy with liquid nitrogen fortnightly for 3-4 months 1

  • Does not require anesthesia
  • Does not scar if performed properly
  • Patients experience moderate pain during/after 1

Expectant management is entirely acceptable for immunocompetent patients with asymptomatic warts, as 50% clear spontaneously within 1 year in children and two-thirds by 2 years 1, 2

Treatment principles:

• Always pare down warts before applying topical treatments 1
• Avoid damaging surrounding normal skin during paring, as this may spread infection 1
• Change treatment modality if no substantial improvement after 3 provider-administered treatments 1

For Corns and Calluses

Primary treatment:

• Manual debridement by trained provider using blade or scalpel 1, 2
  • Most effective method for immediate relief
  • Conservative approach recommended to avoid underlying tissue damage 1

Maintenance therapy:

• Self-management with emery board or nail file after soaking 1, 2
• Urea-based keratolytic creams applied daily to weekly to reduce keratin thickness 1, 2
• Pressure redistribution through proper footwear, padding, or orthotic devices to prevent recurrence 1, 2

Critical caveat: Address the underlying mechanical cause (ill-fitting shoes, foot deformity, abnormal gait) or the lesion will recur 3. Surgical excision of corns has high recurrence rates similar to conservative therapy and may create painful scars 3.

Treatment Pitfalls to Avoid

• Never use chemical corn removers or plasters on diabetic patients due to high complication risk 2
• Avoid overdebridement of any lesion, which can cause pain and tissue damage 1
• Do not use destructive treatments on facial warts without extreme caution due to scarring risk 1
• Recognize that wart treatments do not eradicate HPV infection—recurrence is common 1