Treatment of Periungual Warts
Start with salicylic acid 15-26% applied daily after debridement as first-line therapy, continuing for 3-4 months before switching to cryotherapy if ineffective. 1
First-Line Treatment: Salicylic Acid
Salicylic acid (15-26%) receives the strongest "A" level recommendation from the British Association of Dermatologists for hand warts, including periungual locations. 2, 1
Apply daily after carefully paring or debriding the wart to remove the thick keratin layer that blocks penetration. 1, 3
Continue treatment for 3-4 months with occlusion if possible to enhance efficacy. 2
The medication should be applied after hydrating the skin for at least 5 minutes, covered overnight, then washed off in the morning. 4
Critical Pitfall
- Avoid damaging surrounding skin during paring or application, as this spreads the viral infection through autoinoculation. 3
Second-Line Treatment: Cryotherapy
If salicylic acid fails after 3 months, switch to liquid nitrogen cryotherapy, which has a "B" strength recommendation. 1, 3
Freeze the wart for 15-30 seconds and repeat every 2-4 weeks (fortnightly) for at least 3 months or six treatment sessions. 2, 1
Change treatment modality if no substantial improvement occurs after 3 provider-administered treatments or if warts haven't cleared after 6 treatments. 3
Third-Line Options for Refractory Cases
Intralesional Bleomycin
Bleomycin receives a "C" strength recommendation and is highly effective for refractory periungual warts. 1
Use a diluted concentration of 0.1 U/mL (lower than the 0.1-1 U/mL range in guidelines) administered via translesional multipuncture technique after local anesthesia. 2, 5
In a prospective study, 86.6% of patients achieved complete clearance with only one injection, with minimal side effects limited to localized moderate pain for 2-3 days. 5
Administer every 4 weeks until lesion elimination, typically requiring one to three treatments. 2, 5
Combination Therapy
- For warts not responding to monotherapy, combine salicylic acid with cryotherapy, which demonstrates superior efficacy compared to salicylic acid alone. 3
Contact Immunotherapy
Diphenylcyclopropenone (DPC) or squaric acid dibutylester (SADBE) can be used as third-line options with "C" strength recommendation. 3
After initial sensitization, apply at appropriate strength from twice weekly to every 3 weeks for 3-6 months. 2, 3
Photodynamic Therapy
PDT with CO2 fractional laser achieved 90% complete clearance with no recurrence at 6 months in highly resistant periungual warts. 1
PDT combined with liquid nitrogen cryotherapy and curettage has shown success in recalcitrant cases. 6
Local Hyperthermia
Heat warts to 40-44°C for 30 minutes on three to five consecutive days, with a "D" strength recommendation. 2
This non-contact, noninvasive approach showed complete clearance in refractory pediatric cases after 5 treatments. 7
Surgical Options
Curettage, electrosurgery, or CO2 laser have only level 3 evidence and "D" strength recommendation. 1
Reserve surgical removal for extensive or refractory disease that has failed multiple medical therapies, as scarring and permanent nail changes can occur. 1, 8
Special Considerations
Periungual warts are particularly challenging due to the thick cornified layer and proximity to nail structures. 8
Avoid overtreatment, as scarring (persistent hypopigmentation, hyperpigmentation, or depressed/hypertrophic scars) is common with ablative modalities. 3
Allow sufficient healing time between treatments to prevent permanent nail deformity. 3, 8
Definitive cure is not guaranteed by any therapy, and recurrence can occur even after correct treatment. 8