Lactic acid

How it works

It softens and breaks down hyperkeratotic skin by reducing corneocyte cohesion, and at lower strengths acts as a humectant that increases stratum corneum hydration.

Prescribing in practice

• Apply wart preparations to the lesion only, protecting surrounding healthy skin, as the acid can cause irritation and chemical burns to normal skin.
• Avoid use on the face, anogenital region and on broken or inflamed skin, and avoid warts on the face or near mucosae unless specialist-directed.
• Wart treatment requires regular application over several weeks with paring of dead tissue between applications for effect.

Monitoring

Review the treated lesion and surrounding skin for resolution and for excessive irritation or maceration.

Counselling the patient

• Protect the healthy skin around the wart and apply only to the wart itself.
• Soak and gently file away dead skin between applications, and be persistent as treatment takes weeks.
• Stop and seek advice if the surrounding skin becomes very sore or broken.

Evidence & guidelines

Topical salicylic acid with lactic acid is a recognised first-line self-care treatment for cutaneous warts and verrucae, supported by clinical evidence and guidance.