In most cases a plantar wart, also called a verruca, is treated with salicylic acid from the pharmacy, applied every night to the wart after softening and filing it. It works, but slowly: improvement usually shows in one or two weeks and complete clearance can take up to 12. What you must never do is cut, burn or pull it off yourself.
What a plantar wart is
It is a wart that appears on the sole of the foot. Like all warts, it is caused by the human papillomavirus (HPV), of which there are more than 150 types. The virus gets in through small cuts or cracks in the skin and causes a localised thickening to grow.
Because of how it looks and feels, it is often mistaken for a callus or hard skin. It can be small or spread over a large part of the sole, and it may not hurt at all or be quite uncomfortable when walking or running.
A detail that helps you take it calmly: in children many warts go away on their own, and in general most warts clear up without treatment within about two years. In adults they tend to last longer, and plantar warts are among the hardest to get rid of.
How it spreads
The HPV that causes warts is not very contagious, but it is passed on by contact, and walking barefoot makes it easier for it to reach the sole of the foot. It can also move from one part of your body to another.
The most common situations are:
- Walking barefoot at swimming pools, gym showers and changing rooms.
- Touching or scratching the wart and then another area of skin.
- Using the same file on the wart and on your nails or healthy skin.
- Having cracked skin or small cuts on your feet, which make it easier for the virus to get in.
Over-the-counter treatment: salicylic acid
The first-line treatment you can get at a pharmacy without a prescription is salicylic acid, a keratolytic: it softens and gradually breaks down the surface layer of thickened skin until the wart is gone. In Spain it is sold in several forms authorised by the AEMPS, the Spanish medicines agency:
| Format | Example composition | How it is applied | Duration according to the leaflet |
|---|---|---|---|
| Collodion paint (liquid that forms a film) | Salicylic acid 15% + lactic acid 15% | Once a day, ideally at bedtime, with the brush | Improvement in 1 or 2 weeks; up to about 12 weeks |
| Plaster | Salicylic acid 3.75 mg per plaster | One plaster every night, for about 8 hours, removed in the morning | Usually clears in 3 to 6 weeks; 12 weeks at most |
Both formats share the same limits: they are not applied to moles, birthmarks, warts with hair growing from them, warts on the face or genitals, or on irritated, infected or broken skin. They are not used in children under 2, and between the ages of 2 and 12 only on a doctor’s advice.
How to apply it step by step
- Wash the area with soap and water and dry it well.
- Soften the wart by soaking your foot in warm water for about 5 minutes if it is thick or stubborn.
- File the surface with a file or pumice stone kept only for the wart, without making it bleed. Wash the file after use and never use it on your nails.
- Protect the healthy skin around the wart with a thin layer of petroleum jelly, or trim the plaster so it covers only the wart.
- Apply a thin layer of the paint and let it dry completely, or put on the plaster and secure it.
- Repeat every day at the same time. If you miss an application, don’t apply double: carry on as normal the next day.
Don’t combine the treatment with other wart or corn products on the same area: the effect adds up and the risk of damaging the skin increases.
Side effects and precautions
The most common effects are irritation, itching, stinging, redness or dryness in the area. If the product touches healthy skin it can cause blisters or small ulcers; if that happens, stop for a few days until it settles and start again more carefully.
The collodion paints contain alcohol and ether: they are flammable, so don’t use them near a flame or while smoking, and keep them tightly closed and away from heat.
The collodion leaflet contraindicates it if you have diabetes or peripheral circulation problems, and the plaster leaflet asks you to check with a doctor first in those cases. The reason is that in these feet a small wound can become complicated. In pregnancy and while breastfeeding, ask before using them.
What not to do
- Don’t cut, burn or pull it off. This is the clearest recommendation from health authorities: you can cause a wound or an infection, or spread the virus.
- Don’t stop the treatment at the first sign of improvement. Plantar warts are stubborn and can come back even when they seem to have gone.
- Don’t use the treatment on the face or genitals. Warts in those areas are always treated by a professional.
How to ease the discomfort while it heals
If the wart hurts when you walk, the over-the-counter foot pads or cushions help to spread the pressure. Wear socks and shoes with enough room, and avoid high heels while the treatment lasts.
Treatments a professional can offer
If salicylic acid doesn’t work, a doctor or podiatrist has other options:
- Cryotherapy: freezing the wart to remove it.
- Stronger prescription medicines, or solutions that raise a blister to lift the wart off.
- Electrocautery or laser for the most resistant warts.
- Trimming the thickened skin or calluses that form over the wart.
How to avoid spreading it
- Wear flip-flops or shoes at swimming pools, shared showers and changing rooms: keeping your feet covered is the basic measure against plantar warts.
- Avoid direct contact with the wart, whether it is yours or someone else’s.
- Wash your hands after touching the wart or applying the treatment.
- Keep one file just for the wart and wash it after each use.
- Look after the skin on your feet so it doesn’t crack, since cracks make it easier for the virus to get in.
When to see a doctor
See your doctor, podiatrist or pharmacist, instead of carrying on treating it yourself, if:
- The wart gets worse or stays the same after 7 days of correct treatment, or more warts appear.
- There are signs of infection: pus, discharge, redness spreading in streaks, or fever.
- It bleeds a lot or won’t stop bleeding when you press gently.
- It changes colour or appearance, or you are not sure it is a wart.
- It hurts so much that walking is difficult.
- You have diabetes, poor circulation or a weakened immune system because of an illness or a treatment.
- It is on a child under 12.
This article is for information only and does not replace an assessment by a healthcare professional. If you have any doubts about your particular case, ask your pharmacist or doctor.
Sources: Verufil collodion package leaflet (CIMA, AEMPS) · Verrupatch 3.75 mg medicated plasters package leaflet (CIMA, AEMPS) · Warts (MedlinePlus Medical Encyclopedia, NIH) · Warts, Plantar Warts, Verruca (MedlinePlus, NIH)