What are verrucas and what the difference between a verruca and a corn?  

Although the word sounds like some mythical character, Verrucas are actually small warts. They are easy enough to recognise – typical symptoms are small, white circular patches of abnormally thick skin that grow on the sole of the foot. Often, they have a black spot at their centre, caused by clotted blood vessels. Normally, a Verruca won’t cause problems, but if it’s on a weight-bearing part of the foot, it can be painful and a layer of hard skin is likely to form over it, making the problem worse.  Because verrucas are caused by a viral infection (unlike a corn or callus, which are simply layers of dead skin caused by excessive pressure or friction), they can easily spread to other parts of the foot, or form a mosaic verruca. No, this isn’t the same type of mosaic made by painters, but quite the opposite – a cluster of unsightly warts. One way to tell whether you have a verruca or a corn or callus is to pinch it (gently!) – if it’s painful, it’s probably a Verruca.  Another telltale sign of a Verruca is that the skin’s striae (lines) will become displaced around the affected area, sort of like the circles in a piece of wood.