But all of these conditions are the body's way of alerting you to the fact that the skin on your feet needs to be cared for properly.
But back to the skin itself for a moment.
The thickest skin on your body is that found under your heels. Think about it – it carries your full body weight when you walk, and also provides a cushion of protection for the bones in your heels and feet. This skin will thicken if subjected to abnormal pressure and calluses will even form.
But then the skin on top of your feet is quite thin and pliable, contains hair follicles and has almost no fat underneath it.
The skin on your feet often also suffer the indignity of being squeezed into ill-fitting, but fashionable shoes or being closed up in nylon socks or sports shoes that might not allow them to breathe.
No wonder skin problems occur so often on people's feet. In fact, very few people go through life without ever experiencing some problem related to the skin on their feet.
Corns and calluses
When there is excessive pressure or friction on the skin, calluses and corns form to protect the skin and the structures beneath it. Calluses on the feet can develop into corns.
Calluses usually develop on the soles of the feet, on the parts that bear most of the pressure when you walk and stand. A callus, when it thickens, can cause added pressure inside a shoe against the skin.
Walking barefoot can cause thick calluses under the soles, but if someone develops calluses even if they wear shoes most of the time, it is a sign that there is an underlying problem (such as bunions or flat feet) which is causing pressure between the skin and the bone underneath it.
Read more about corns and calluses.
Blisters are often the result of continuous friction caused by ill-fitting shoes. Blisters are filled with clear fluid that accumulates under the skin. Sometimes they can also fill with blood if they have ruptured a small blood vessel.
They occur when feet get hot and sweaty, and the socks start sticking to the feet. The sock and foot then rub against each other and the inside of the shoe. Fluid fills up a space between layers of skin to protect the area, like a small balloon. That's how blisters form.
Usually blisters drain by themselves in a few days, but if there is continued friction on the site of the blister, it may become infected.
Find out more about blisters
Plantar warts are caused by the human papilloma virus, which can be acquired in areas where people commonly go barefoot. They grow into the sole of the foot and can cause pain.
It can take a few months from initial exposure until warts appear. They are contagious and can spread at public swimming pools or showers. The body develops immunity against these viruses over the years, so that plantar warts are more common in children than adults.
The warts appear as small, bumpy growths on the soles of the feet, measuring up to 5 cm across, sometimes with small black spots on the surface. They can become pressed into the sole of the foot. Pinpoint bleeding may occur when they are traumatised or scratched. They can be extremely tender when standing or walking.
These warts eventually disappear by themselves, but because they are painful, most people prefer to have them treated. It is best to have them seen to by a doctor or podiatrist and not to treat them at home.
Find out more about plantar warts.
Athlete's foot is the most common and most persistent of the fungal infections that affect the feet.
It refers to a dermatophyte infection of the spaces between the toes, usually between the fourth and fifth toes. It may occur in association with other fungal skin infections, such as fungal infection of the toenails, feet or groin.
The fungi that cause athlete's foot thrive in warm, moist areas. Susceptibility to this infection is increased by poor hygiene, occlusive (closed-up, such as tennis shoes) footwear, prolonged moist skin, and minor skin or nail injuries.
Tinea infections are contagious, and can be passed through direct contact, or contact with items such as shoes, stockings, and shower or pool surfaces.
The condition usually responds to self-care, but if the infection persists, long-term medication and preventive measures may be needed.
Find out more about athlete's foot.
If your hands were encased in layers of cotton and leather every day they’d smell a little like your feet by 6 pm. That’s because your hands and feet are the extremities with the highest number of sweat glands on the body – more than 600 per square centimetre.
Feet smell, because the perspiration emanating from them can’t evaporate inside closed shoes. Warmth and moisture create a perfect incubator for bacteria, which produce fatty acids that can smell strongly. These conditions are also ripe for the bacteria that can cause athlete’s foot.
One of the main contributors to odours from the feet is the wrong sort of shoe or sock. Shoes that have plastic, synthetic or cardboard linings, don’t allow sweat to evaporate. It is a good idea not to wear the same shoes every day, so they get a chance to dry out.
Nylon or synthetic socks should be replaced with socks that are a mixture of wool and cotton, or ones with no more than 40 percent man-made fibre such as rayon or nylon. Obviously you should wear clean socks each day.
If you have hard or cracked skin, you, or preferably your podiatrist, need to remove some of it with a pumice stone. Hard skin can go soggy and harbour bacteria. Visit a podiatrist if the soles of your feet have a pitted appearance – you may have a bacterial infection called pitted keratolysis.
Also consider buying some tea tree oil and putting a few drops into a basin of warm water and bathe your feet in it for about 20 minutes at the end of each day. Speak to your doctor or pharmacist about an aluminium chloride spray that you can apply to your feet as long as you don’t have athlete’s foot or any open sores.