What are the treatment options for a verruca (wart)?

Treatment Options for Verruca (Warts)

Salicylic acid 15-40% applied after paring the wart is the recommended first-line treatment for most cutaneous warts, with cryotherapy reserved as second-line therapy when salicylic acid fails after 3 months. 1, 2, 3

First-Line Treatment: Salicylic Acid

Salicylic acid works by promoting exfoliation of infected epithelial cells and potentially stimulating host immunity, achieving a mean cure rate of 49% versus 23% for placebo. 2

Application Technique

• Pare or debride the wart before each application to remove the thick keratin layer 1, 2, 3
• Apply salicylic acid 15-40% topical paint or ointment daily to the wart surface 1, 2, 4
• Consider occlusion with adhesive plaster to improve efficacy 2
• Continue treatment for at least 3 months before determining failure 3

Concentration by Location

• Plantar and hand warts: 15-40% topical paints or ointments 2, 3
• Plane warts: 2-10% cream/ointment or cautious use of 12-17% paint without occlusion 2
• Facial warts: Salicylic acid paints are contraindicated due to risk of chemical burns; only 2% creams may be considered 2

Critical Safety Warnings

• All but very low-strength salicylic acid can cause chemical burns 2
• Contraindicated in areas of poor healing such as neuropathic feet 2
• In children under 12, limit treatment area and monitor for salicylate toxicity (tinnitus, nausea, vomiting, hyperventilation) 3
• Avoid use during varicella infection or influenza-like illnesses due to Reye syndrome risk in children 3

Second-Line Treatment: Cryotherapy

If salicylic acid shows no improvement after 3 months, switch to cryotherapy with liquid nitrogen applied fortnightly for 3-4 months. 1, 3

• Cryotherapy destroys warts through thermal-induced cytolysis 1
• Pain after application and subsequent blistering are common 1
• More aggressive cryotherapy regimens combined with salicylic acid may be more effective but cause worse side effects 2, 3, 5

Location-Specific First-Line Approaches

Filiform Facial Warts

Cryotherapy, curettage, or hyfrecation are the most effective first-line treatments for filiform warts on the face, with the best outcomes for morbidity and mortality. 6

• Destructive and caustic agents can produce scarring on facial skin and should be used with caution 6
• Glycolic acid 15% can be used as an alternative with less scarring risk 6
• Imiquimod cream may be effective through immune-modulating properties 6

Anogenital Warts

For external genital warts, patient-applied podofilox 0.5% solution or provider-applied cryotherapy or TCA/BCA 80-90% are recommended options. 1

• Apply TCA/BCA sparingly only to warts until white "frosting" develops 1
• Podophyllin is contraindicated in pregnancy due to dangerous systemic effects 1, 2
• Surgical removal is advantageous for large numbers or areas of warts 1

Alternative Treatments for Resistant Warts

When first and second-line treatments fail after adequate trials:

• 5-Fluorouracil 0.5% combined with salicylic acid 10% shows 63% clearance versus 11% for salicylic acid alone 1
• Dithranol 2% cream showed 56% cure rate versus 26% for salicylic acid/lactic acid combination 1
• Formaldehyde 3% soaks reported 80% cure rate in plantar warts 1, 3
• Glutaraldehyde 10% paint equivalent to salicylic acid but risk of deep necrosis with repeated application 1, 3
• Laser therapy (CO2 or pulsed-dye laser) for recalcitrant cases 1, 6
• Photodynamic therapy for treatment-resistant cases 1, 6

Surgical Options

Surgical removal by tangential excision, curettage, or electrocautery eliminates warts at a single visit but requires clinical training and longer office visits. 1

• Most beneficial for patients with large numbers or extensive areas of warts 1
• Control depth of electrocautery to prevent scarring 1
• Suturing is neither required nor indicated in most cases 1

Important Clinical Pitfalls

• Avoid damaging surrounding skin during paring as this can spread the viral infection 6, 2, 3
• Patient compliance with salicylic acid is often poor due to irritation of surrounding skin 3
• Plantar warts have lower cure rates than other sites due to thicker cornified layer 1, 3
• Warts in children often resolve spontaneously within 1-2 years; watchful waiting may be appropriate 1, 3
• Treatment should continue for adequate duration (3-4 months) before determining failure 3