Intralesional Acyclovir Versus Intralesional Zinc Sulphate in the Treatment of Plantar Warts

Viral warts represent benign epidermal proliferations associated with human papillomavirus (HPV) infection. HPV is a double-stranded DNA virus with more than 150 identified types, several of which have a predilection for cutaneous tissues and can produce distinct clinical forms of warts. Transmission occurs through direct skin-to-skin contact, indirect contact with contaminated surfaces, or autoinoculation, as when a wart is scratched or picked and virus is carried to a new site.

Cutaneous warts occur worldwide, with an estimated overall population prevalence of roughly 10%, rising to 10-20% among school-aged children. Although warts may develop at any age, incidence climbs through childhood and peaks between 12 and 16 years. Most lesions are asymptomatic, but they are not without consequence: warts can produce cosmetic disfigurement and psychosocial distress, and those on weight-bearing surfaces such as the plantar skin can become painful with walking or pressure. The principal clinical types are common, plantar, plane, filiform, and genital warts.

Plantar warts, the focus of the present study, arise on the sole and are most commonly attributed to HPV types 1, 2, 4, 27 and 57. Because of the constant pressure exerted by weight-bearing, these lesions tend to grow inward rather than outward and are often covered by a thick overlying callus that can mask the lesion and delay diagnosis; adjacent warts may also coalesce into a mosaic pattern. Unlike many other cutaneous warts, plantar warts are frequently symptomatic, producing a sharp, well-localized pain on walking or standing that can meaningfully impair mobility and daily activities. Clinically, they are distinguished from corns and calluses by the presence of pinpoint black dots, corresponding to thrombosed dermal capillaries, and by interruption of the normal skin lines across the lesion.

Several therapeutic modalities are available for cutaneous warts, including destructive methods such as salicylic acid, cryotherapy, silver nitrate, electrosurgery and pulsed-dye laser, antiproliferative agents such as formaldehyde, vitamin D3, bleomycin, 5-fluorouracil, podophyllin and podophyllotoxin, topical immunological agents such as imiquimod ; However, treatment remains challenging because of variable efficacy, prolonged treatment courses, recurrence and adverse effects. No single treatment option is considered gold standard.

Intralesional therapies are an emerging and effective approach for treating recalcitrant warts. Several immunotherapeutic agents for warts including vitamin D3; tuberculin purified protein derivative (PPD); Candida antigen (Candida); the measles, mumps, rubella (MMR) vaccine, BCG, zinc sulphate and antivirals such as acyclovir have demonstrated variable complete response rates in randomized controlled trials. Unlike various other treatment options, immunotherapeutic approaches upregulate the immune system to recognize and destroy the lesions at both the target site and distant locations.