Corns, Verrucas and Callus - a pain in the foot!
By Marcel Wadman, Podiatrist and Practioner
Corns, Verrucas and Callus’s are very common and most of us will get one or more of
these seemingly small conditions during our life time. They affect both male and female
patients alike and may exist alone or together.
So let’s start at the basics. The corn is a small clearly defined hard plug of skin often
found on the weight bearing areas of the foot. They are painful on weight bearing and
when direct pressure is applied. If the corn has been present for a long time, it may be
covered by an area of hard skin that we call a “Callus”. Contrary to common belief, they
do not grow into the foot but are caused by skin that is compacted.
Our skin is made up of various layers and is constantly growing from the base layer to the
top. This occurs on average over a 30-70 day period. Small areas of pressure accelerate
this and tissues retain their adhesive properties that are usually lost in their journey to the
top layer of the skin called the Epidermis. And so skin is constantly produced at this area
and not lost, leading to a hard core of skin, bottom to the top, a corn! They can be very
painful and will remain until removed and the source of pressure removed. “What causes
pressure?” I hear you say. Well, it can be damage to the lining of a shoe or a prominent
bone on a hard surface, anything that can cause a finite area of pressure and friction to
the skin of the foot.
Corns can be found on the top or base of the foot and even between the toes, most often
between the little toe and it’s neighbour. A Chiropodist should be able to remove the corn
with minimum discomfort. If your corn is reoccurring, then it is most likely that too much
time is lapsing between debridement. Any remaining corn, or reoccurring corn is causing
sufficient pressure for the cycle to continue.
As for the Verruca, this is often confused with the corn but it is quite different. This is
caused not by pressure or friction but by a viral infection of the human papilloma virus
(HPV) and will on occasions and in some individuals, resolve without treatment. Unlike a
corn, the verruca is very painful. If it is squeezed and if cut, can bleed for a considerable
time. The duration and number of verrucas one has can be directly related to the state of
one’s immune system and any large number that have been present for some time should
be investigated. Treatment is via Cryo surgery (freezing) chemicals applied to the verruca
only and more recently laser. In reality, most have a very similar cure rate but in all cases,
I would recommend that the treatment is supervised by a Podiatrist. Verrucas do not have
overlying hard skin but project above the line of the epidermis.
Verrucas can be present in various forms. They can be singular or multiple or multiple
tightly packed individual verrucas and as most people know, verrucas can be contagious.
Callus’s, like corns form in response to direct mechanical stress. This may be intermittent
but will involve shear, friction, torsion and tension in some combination. The patterns and
location of these areas of hard skin often reflect the biomechanical origins of the callus.
Thick hard areas need to be reduced to prevent further damage to the underlying tissues
and structures. Left, callus’s can become painful to the point where gait is altered to avoid
the associated discomfort. If only it was that simple! In fact, there are many other non
mechanically induced forms of callus or hyperkeratosis. Through inherited pathways such
as Dariers disease, Mal de Meleda, Ichthyosis or even acquired as a chronic contact
dermatitis, Lichen planus or Reiter’s disease. These have varying presentations but in
most cases it will be normal hard skin formed from mechanical stress. As they say,
“If in doubt, get it checked out by your Podiatrist or Chiropodist”