A verruca is the result of an infection from certain strains of the human papillomavirus (HPV). It appears like a small, dark, puncture mark later turning grey or brown. It may become rough and bumpy with a cauliflower-like appearance. It can also develop a black spot in the middle, as the result of bleeding. A verruca can grow in diameter, may spread into a cluster.
Verrucae are typically painless, but the disruption they cause to the skin if one develops on a weight-bearing area such as the ball or the heel of the foot, can cause a sharp, burning pain. The pressure of weightbearing can cause the resulting hard skin to protrude painfully into the skin.
Verrucae are harmless and will spontaneously heal over time without treatment, but can persist for years. The general policy in the UK is to only treat them when they are causing pain. There are a number of treatments available for warts. However, no single treatment is 100% effective, and sometimes the wart may return. The aim of treatment is to remove the wart without it returning and without leaving any scarring. Treatments include, acids, cryotherapy and surgery.
Some treatments may cause side effects such as mild pain, blistering and skin irritation around the wart.
Many treatments, such as creams, gels, paints and medicated plasters, are available over-the-counter from pharmacies. It has been shown that acid is effective at treating verrucae. Acids are not selective and also destroy the surrounding healthy skin, so it is important to have the treatment professionally applied, particularly if you are vulnerable or high risk. Before applying the treatment excess skin around the affected area should be reduced in order to improve its efficacy. Follow the instructions that come with the medication. You may need to apply the treatment daily for 12 weeks or longer. You should stop the treatment if your skin becomes sore and seek advice from your GP or pharmacist. Also consult your GP before using over-the-counter treatments that contain acid if you have poor circulation – for example, if you have a condition such as diabetes or peripheral vascular disease as there is an increased risk of damage to your skin, nerves and tendons.
In cryotherapy a freezing agent is sprayed onto the veruca in order to destroy the affected skin cells. After treatment, a painful blister may form. Cryotherapy usually takes 5-15 minutes and it can be painful. Large verrucae sometimes need to be frozen a number of times, a week or so apart, before they clear up.
Cryotherapy is not usually recommended to treat young children because they may find the treatment too painful, or it may be difficult for them to stay in the same position while having the treatment.
Possible side effects of cryotherapy include:
• pain and blistering
• your skin may become darker (hyperpigmentation) or lighter (hypopigmentation), particularly if you have black skin
• your nails may develop an abnormal change in shape or structure if cryotherapy is used to treat warts that develop under the nails (periungual warts)
Cryotherapy is sometimes carried out at GP surgeries or at hospital skincare clinics. However, it may not be available on the NHS in all areas of the country.