Fissures can form on the heel of the foot when the feet are dry and the skin cracks under the pressure. Calluses form in areas where there is friction, generally from constant rubbing of footwear.
Fissures can develop if the heel becomes excessively dry and the skin begins to crack, also if the area is wet causing the skin to soften and making it more likely to split. The feet are under pressure from your body weight and the skin, being dry and no longer pliable and elastic, splits and cracks
Cracks and splits in the skin can be painful and unsightly but also can allow bacteria to penetrate, possibly leading to infection. This can be very problematic in a high-risk foot, such as in a diabetic patient.
Some common causes of cracked heels can be as simple as standing for long periods, wearing inappropriate footwear, or spending lots of time with bare feet. Being overweight, or certain skin conditions such as eczema and psoriasis can also cause these problems.
Treatment may involve removing (debriding) the hard skin with a scalpel or foot file and applying appropriate moisturising cream to the area. I will then advise on appropriate footwear and foot care to restore the area of dry skin to its natural state. If an infection is present then I may refer you to your GP for a course of antibiotics.