In short. How to tell a verruca from a corn, why the distinction matters, and what makes warts on the sole of the foot stubborn to treat.
Key points
- Squeeze the lesion from the sides: a wart hurts, a corn does not.
- Press straight down: a corn hurts, a wart less so.
- Break the surface pattern of the skin: the ridges of the skin run around and through a wart, and are interrupted by a corn.
A painful lump on the sole of the foot is usually one of two things: a plantar wart, or a corn. They look similar, they are caused by completely different processes, and they are treated in completely different ways. Treating a corn as a wart, or the other way round, wastes months and can make the problem worse.
What a plantar wart is
A plantar wart, or verruca, is a human papillomavirus infection of the skin of the sole. Because the sole bears weight, the wart is pushed inwards rather than growing outwards, so it appears as a thickened, flattened area of skin, sometimes with a rough surface and tiny black dots from small clotted vessels. It is often painful when squeezed side to side. Warts can be single or clustered, and they can spread along the sole over months.
What a corn is
A corn is not an infection. It is a cone of thickened, hardened skin formed in response to repeated pressure and friction, with the point of the cone pressing into the tissue beneath. It is painful when pressed directly downwards, which is the opposite of the squeezing test for a wart. Corns sit over bony prominences or under pressure points, and they are associated with tight footwear, foot deformity, and reduced sensation in the feet.
Why the distinction matters
A corn treated with wart preparations becomes raw and painful without ever resolving, because the cause is mechanical. A wart treated only with padding and footwear change may improve but rarely clears, because the virus is still present. The two are told apart clinically, and where there is doubt, paring the surface helps: a wart bleeds in fine pinpoints from its vessels, while a corn shows a uniform, hard, translucent core.
Treatment of plantar warts
Treatment options include topical preparations applied consistently for weeks or months, freezing in the clinic, and other destructive methods, sometimes in combination. All are slower and less reliable on the sole than on the hand, because the thick keratin barrier protects the virus and the area is under constant pressure. Recurrence is common, and no treatment is guaranteed. Where a wart is not painful and not spreading, waiting is reasonable, especially in children, since many clear on their own. Anyone with diabetes, poor circulation or reduced sensation in the feet should not treat a foot lesion at home or pare it, because the risk of an ulcer is real. Footwear that fits, cushioning, and treatment of any foot deformity matter as much as the wart treatment itself.
Telling them apart
Squeeze the lesion from the sides: a wart hurts, a corn does not. Press straight down: a corn hurts, a wart less so. Break the surface pattern of the skin: the ridges of the skin run around and through a wart, and are interrupted by a corn. A wart may show tiny black dots; a corn shows a hard central core.
Do not self-treat, and seek review, if
- You have diabetes, poor circulation or reduced sensation in the feet, or any open sore on the foot.
- The lesion is bleeding, ulcerated, changing, or the diagnosis is not clear.
- Pain is worsening, you are limping, or the lesion keeps returning after treatment.
Frequently asked questions
How can a clinician tell a plantar wart from a corn?
Squeeze the lesion from the sides: a wart hurts and a corn does not. Press straight down: a corn hurts and a wart less so. The skin ridges run around and through a wart and are interrupted by a corn, and a wart may show tiny black dots.
Why do plantar warts respond less reliably to treatment than warts on the hands?
The thick keratin barrier of the sole protects the virus, and the area is under constant pressure, so every treatment is slower and less reliable there. Recurrence is common, and no treatment is guaranteed.
Why does treating a corn with wart preparations make it worse?
A corn is not an infection. It is a cone of thickened, hardened skin formed in response to repeated pressure and friction, so wart preparations make it raw and painful without ever resolving it. Padding and better-fitting footwear address the actual cause.
Risks & Limitations
- Treatment fails if the diagnosis is wrong, or if the course is shorter than the infection requires.
- Relapse after apparent cure is common — reinfection from feet, nails, pets, household contacts or shared floors.
- Oral antifungals interact with many common medicines and need liver and blood monitoring.
- Skin colour change and scarring can follow infection, and may take months to fade or be permanent.
- Warts recur after any treatment, and no single treatment is guaranteed to clear them.
- Antiviral treatment for herpes works best started early, and it does not remove the virus.
- Nail fungus treatment takes months, and a proportion of people relapse afterwards.
When to Seek Care
- Fever with a spreading rash, or pain far worse than the skin appears — seek emergency care the same day.
- Rapidly spreading redness, swelling, dusky or blistered skin, or numbness over the area.
- Shingles near the eye or on the tip of the nose, or eye pain, redness or blurred vision.
- Blistering skin, or a rash involving the eyes, mouth or genitals.
- Any skin infection with fever in someone who is immunocompromised, diabetic, or taking steroids or chemotherapy.
References & Further Reading
- American Academy of Dermatology (AAD) — public and clinical guidance
- World Health Organization (WHO) — skin and infectious disease resources
- Centers for Disease Control and Prevention (CDC) — infection prevention and treatment guidance
- Chinese Medical Association, Dermatology Branch — clinical guidance
- Cochrane Library — systematic reviews in skin infection and dermatology
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.