A hard lump appears on the sole of your foot. It hurts when you walk, it has not gone away after a fortnight, and a search online has left you no clearer about whether you are dealing with a corn or a wart.

The confusion is understandable, since both present as thickened patches of skin in weight-bearing areas and both can be tender. The treatments differ substantially, though, and applying the wrong one wastes weeks. Telling them apart is the first thing any doctor for feet will do before recommending anything.

Two problems with entirely different causes

A corn is the skin protecting itself. Repeated pressure or friction in one spot prompts the skin to thicken, forming a dense core that presses inward as it grows. Nothing is infecting the area. The lump is a mechanical response to load, which is why corns tend to appear over bony prominences, on the ball of the foot, or on and between the toes.

A plantar wart, or verruca, is a viral skin lesion caused by human papillomavirus entering through a small break in the skin. It is a genuine infection, which means it can spread to other parts of the foot and, in shared wet environments, to other people. Changing rooms, pool surrounds and communal showers are the usual settings for transmission.

How to tell them apart at home

A few practical checks separate the two reasonably well.

  • Skin lines: the natural lines of the skin run across a corn, whereas a wart interrupts them and the pattern stops at its edge
  • Tiny dark dots: warts often show small black or brown specks, which are clotted capillaries feeding the lesion
  • Direction of pain: a corn hurts most with direct downward pressure, while a wart is typically more painful when pinched from the sides
  • Location: corns form where pressure concentrates, while warts can appear anywhere on the sole, including areas that take no load
  • Number: warts often cluster or appear in several places, whereas a corn is usually solitary and predictable

The side-squeeze test is the most useful of these for most people. It is also imperfect. Lesions that have been picked at, pared down or treated with over-the-counter acid can look thoroughly ambiguous, and a corn sitting directly over a wart is more common than you might expect.

Why the distinction changes the treatment

Corn management is mechanical. The thickened tissue and its core are carefully removed, which usually brings immediate relief, and then the pressure causing it is addressed through footwear changes, padding or prescription insoles. Remove the tissue without changing the load and the corn simply returns.

Wart treatment targets a virus. Options include cryotherapy, chemical cauterisation and needling, and courses typically run across several appointments as the body’s immune response is prompted to clear the infection.

Treating a wart as a corn achieves nothing beyond thinning the surface, while the virus remains and often spreads. Treating a corn as a wart means enduring uncomfortable treatments for a problem that would resolve with a pressure adjustment.

Timing offers another clue. Corns build slowly across weeks or months, usually in step with a new pair of shoes or a change in activity, and they tend to reappear in exactly the same spot once removed. Warts can appear within a matter of days and often follow a period of barefoot time in a shared facility, which is why a swimming term at school so often precedes one.

Where children are concerned

Children develop warts far more readily than corns, since their immune systems have had less exposure to the virus and their weekly routines involve swimming lessons and barefoot activity. Warts on a child’s foot deserve a proper look before anything is applied, as covered in the discussion of why plantar warts in active kids turn up so frequently.

Over-the-counter acid preparations are best avoided on young feet without advice, since children’s skin is thinner and the surrounding healthy tissue is easily damaged.

Reducing the chance of either returning

Prevention differs for the two problems, which is another reason the diagnosis is the starting point. Corns respond to load management: shoes with adequate depth and width, socks that do not bunch, and insoles that redistribute pressure away from the spot taking the brunt of it.

Warts call for hygiene measures instead. Wearing pool slides in changing rooms and communal showers, drying between the toes properly, keeping a separate towel for the feet while a lesion is present, and covering the area before swimming all reduce transmission to other people and to other parts of your own foot.

Why home treatment so often disappoints

Medicated plasters and pumice stones remove surface tissue, which is the visible part of the problem and rarely the important one. A corn’s core sits deeper than most people reach, and a wart’s roots extend below the surface layer that a plaster affects.

Cutting either with a blade at home carries real risk of infection, particularly for anyone with diabetes or reduced circulation in the feet. Those groups should have any lesion on the sole assessed rather than managed at home. Outcomes vary between individuals, and stubborn lesions sometimes need several rounds of treatment before they settle.

Getting a clear answer

A trained eye settles the question in minutes, usually by paring back a thin layer of surface tissue and observing what lies underneath. From there the right treatment can start immediately instead of after months of guesswork.

If a stubborn lump on your foot has outlasted your patience, Feet First Podiatry Clinic can identify what it is and treat it appropriately. Get in touch to arrange an assessment.