Why some plantar warts are hard to eradicate
Plantar warts are caused by human papillomavirus (HPV) growing within the thick, pressure-bearing skin of the sole. In mosaic warts, multiple viral colonies coexist under a shared callus “roof,” allowing some areas to survive when others are injured. This architecture can make treatments appear to work temporarily while the infection persists underneath.
Cryotherapy (freezing)
Cryotherapy uses liquid nitrogen to freeze wart tissue and the tiny blood vessels that supply it. This damages infected cells and produces the characteristic black dots (thrombosed capillaries) seen in plantar warts.
However, cryotherapy does not reliably penetrate thick plantar callus. In mosaic warts, freezing may kill some viral islands while leaving others protected beneath keratin. This can produce cycles of improvement and relapse, as seen in the early phases of the Timeline.
Salicylic acid and keratolytic therapy
Salicylic acid dissolves keratin — the thick, hardened skin that protects plantar warts. By removing this barrier, the treatment exposes viral tissue to chemical destruction and to the immune system. High-strength pads (40%) are often used for thick plantar and mosaic warts.
In this case, earlier low-strength liquid acid and duct-tape occlusion were insufficient to penetrate the wart’s callus roof. Once high-strength pads were applied consistently, the underlying wart architecture was dismantled and removed.
Why redness is misleading in acid treatment
Many 40% salicylic acid pads contain red-orange dye. As the pad dissolves keratin and penetrates deeper layers, the dye stains pores, fissures, and dead tissue. This can look like bleeding but does not indicate active viral tissue. The Timeline shows how dye can make dying wart structure appear dramatic even as the virus is being eliminated.
Debridement
Soaking and gentle filing remove dead keratin so treatments can reach infected tissue. This reveals the internal structure of mosaic warts — lobules, pits, and capillary remnants — that are invisible when dry. Debridement explains why soaked or trimmed photos often look worse than dried ones even when healing is underway.
The healing and remodeling phase
After wart tissue is destroyed, the sole must rebuild normal skin. This process produces pits, rings, dots, strings, and mottled color as dead wart scaffolding is shed and replaced by new epidermis. Skin lines gradually cross the area again, signaling true resolution.
The final phase of the Timeline documents this slow remodeling process — the part most often mistaken for recurrence.
Educational only. This site documents one case history and does not provide medical advice.