Warts and Verrucae

Overview

This summary has been developed for use by community pharmacists and therefore only covers the information relevant to this setting. Areas covered include: an overview of the condition, differential diagnoses, advice for those with the condition, and treatment. Please refer to the full guideline for the complete set of recommendations.

Introduction

• Warts are small, rough growths which are caused by certain strains of the human papilloma virus (HPV). They can appear anywhere on the skin but are most commonly seen on the hands and feet.
• A verruca (also known as a plantar wart) is a wart on the sole of the foot.
• Cutaneous warts are common, and most people will have them at some point in their life.
• Warts are usually spread by direct skin-to-skin contact, or indirectly via contact with contaminated floors or surfaces (for example in swimming pools or communal washing areas).
• Benign warts in immunocompetent people almost never undergo malignant change.
• Warts are diagnosed from their typical appearance:
  • Common warts are firm and raised with a rough surface that resembles a cauliflower (common on knuckles, knees, and fingers).
  • Plane warts are round, flat topped, and yellow (common on the backs of hands).
  • Filiform warts are long and slender (common on the face and neck).
  • Plantar warts (verrucae) grow on the soles of the feet, often have dark dots in the centre, and may be painful.
  • Mosaic warts occur when palmar or plantar warts coalesce into larger plaques on the hands and feet.
• Although warts can be cosmetically unsightly, they are not harmful, usually do not cause symptoms, and most resolve without treatment.
• Advice should be offered on reducing the risk of transmission and limiting personal spread of warts. Treatment should be considered if a wart is painful, cosmetically unsightly, persistent, or the person requests treatment.
  • For the treatment of other warts in adults and older children, options are topical salicylic acid, cryotherapy, or a combination of both (cryotherapy is not recommended for younger children).

Management

From age 12 months onwards.

Which Treatments are Recommended in Primary Care for Warts or Verrucae?

• Facial warts should not routinely be treated in primary care.
• For non-facial warts:
  • For adults and older children, treatment depends upon what has been tried already and what the person prefers. Options include:
    • Topical salicylic acid (15–50%) applied daily for up to 12 weeks. For more information on available topical salicylic acid preparations that may be prescribed on an FP10 see the section on Topical salicylic acid.
    • Cryotherapy with liquid nitrogen (usually carried out every 2 weeks for up to 3–4 months until the wart is gone, or for a maximum of 6 treatments). Note, cryotherapy is only suitable for older children who are likely to tolerate this treatment. For information on who should not receive cryotherapy, see the section on Contraindications to cryotherapy at cks.nice.org.uk.
    • Combination therapy with salicylic acid and cryotherapy (applying topical salicylic acid preparations between cryotherapy sessions once the scabbing from cryotherapy has resolved).
    • A shorter cryotherapy freeze (for example 5-10 seconds ) or a weaker strength topical salicylic acid preparation (for example 17% or less) is recommended for plane warts on the back of the hands, as scarring is more likely to occur.
  • For younger children, offer treatment with topical salicylic acid applied daily for up to 12 weeks.
    • Do not use cryotherapy in younger children.

Topical Salicylic Acid

Who should not receive topical salicylic acid?

• Topical salicylic acid can cause irritant burning and should not be used on:
  • The face.
  • Intertriginous or anogenital regions.
  • Moles or birthmarks.
  • Warts with hair growing out of them, red edges, or an unusual colour.
  • Open wounds, irritated or reddened skin, or any area that is infected.
  • Areas of poor healing such as neuropathic feet.

How should topical salicylic acid be applied?

• Topical salicylic acid:
  • Apply the treatment once a day, at night.
  • Before applying, debride the surface of the wart or verruca with an emery board and/or soften the area by soaking it in warm water for 5–10 minutes.
  • For subsequent applications, peel off any film remaining from the previous application and debride and soak as above.
  • Avoid applying the treatment to the surrounding skin by applying carefully to wart and protecting the surrounding skin with soft paraffin or plaster.
  • Do not  apply to the face or areas that are extensively affected because of an increased risk of skin irritation and scarring.

What are the adverse effects of topical salicylic acid?

• Topical salicylic acid therapy may cause chemical burns and irritation of the skin.

What Advice Should I Give to Someone With Warts or Verrucae?

• Advise that:
  • Although warts can be cosmetically unsightly, they are not harmful; usually they do not cause symptoms, and resolve without treatment.
  • Warts are contagious, but the risk of transmission is thought to be low.
  • To reduce the risk of transmission:
    • Cover the wart with a waterproof plaster when swimming. The Amateur Swimming Association (ASA) states that the use of swimming socks should be discouraged and that a waterproof plaster is sufficient.
    • Wear flip-flops or other appropriate foot wear in communal showers.
    • Avoid sharing shoes, socks, or towels.
  • In order to limit personal spread (auto-inoculation):
    • Avoiding scratching lesions.
    • Avoiding biting nails or sucking fingers that have warts.
    • Keeping feet dry and changing socks daily.
  • Children with warts or verrucae should not be excluded from activities such as sports and swimming, but should take measures to minimize transmission.
• Offer online patient information leaflets on warts and verrucae such as those provided by NHSA-Z and the British Association of Dermatologists (pdf).

What Else Might It Be?

• Differential diagnoses of warts include:
  • Hyperkeratotic lesions of the hand or feet for example:
    • Actinic keratosis.
    • Seborrheic keratosis.
    • Knuckle pads.
    • Squamous cell carcinoma.
    • Focal palmoplantar keratoderma. Lichen planus.
    • Angiokeratoma.
  • Corns or calluses of the feet.
  • Malignant melanoma.