Cracked heels are a common foot problem that is generally caused by extremely dry skin (xerosis). This condition, which often refers as foot fissures, especially affects the heels because their thickened dry skin is more likely to crack often due to mechanical factors that increase pressures in that area (i.e, prolonged standing or the way you walk, especially if you are obese). Also, wearing open backed shoes, as most of us do so on those hot summer days, unfortunately allows the fat on the heel to expand sideways and increases the pressure to crack. Not drinking enough water and poor nutrition are also risk factors for cracked heels. You are right to state that this condition can be the result of a fungal infection (i.e., athlete's foot) in the skin on the feet. If left untreated, these cracked heels may develop into deep heel fissures that can allow bacteria to enter the body, leading to infection and illness
. A cracked heel may also be a sign and symptom of a more serious medical condition, such as diabetes or a thyroid disease. A break in the skin must always be treated to avoid potential serious infections so I suggest that you seek prompt medical care from a podiatrist
as well as to rule out any serious medical condition. Good luck.