The medical reason for most cracking skin is fungal in nature.
Cracked thickened skin around the heel is called Tinea Pedis "Moccasin Type".
This fungus is EXTREMELY hard to get rid of. Even when one might feel they have "won the battle" it tends to re-appear again.
I got mine from watering the front lawn and standing on the wet lawn barefooted.
The fungus is what causes the dead layers of skin to "build up" and get thick... the same as it does to a toenail with fungus.
Tea tree oil, apple cider vinegar ,and urine ( urea) are all effective against fungus, but it is a battle you cannot rest from. Prevention is a big key but also do not stop treating your skin, even if you think it has gone away. I would wait 2 months of "clear skin" before I stopped treating.
Bleach the floors of your showers every other day. Change socks 2 times a day- don't share shoes, don't walk barefooted outside, especially on lawns,
wear athlete's foot powder inside socks, change liners in tenny shoes. Don't buy cheap shoes made out of plastic made to look like leather- buy only leather. Scraping the outer tough layer of calloused skin is a must before you put on the tea tree oil, bag balm, or whatever. Tea tree oil is great on toenail fungus 2 x a day (the entire nail and the cuticle where the nail emerges)- but I think if you use it around your heel, after you apply it put some flexol or bag balm over the top of that. Dont just use tea tree oil alone on heels. With a toenail, one day of "missed" application will make you start all over from the beginning. The entire nail must have been grown out and cut off for you to be fungus free. So it is the same with the heels.
I have been known to let me heels go, and then needed to scrape my heels with tough grit sandpaper or even the edge of a scissors if I cant find the sandpaper- anything that will get that thick skin off so you can treat the fungus below it. Above all stay on top of it and treat every day, even if you think it better. Treat (still nightly) for at least a month or two after all cracking and dryness is gone.
Internal fungal overgrowth in the gut , lowered immune systems from antibiotic use , and 'acidosis' from bad eating habits will help fungal colonies get "a hold". The more healthy your immune system is, the less likely this parasite can get on board. That is why we see these kinds of parasitic infections are rampant in the elderly. keep the gut healthy by avoiding taking antibiotics, and if you must take them, get a prescription for an antifungal or if they wont give you one, use a probiotic like Culturelle. RAW milk helps fight gut yeast due to a naturally occuring yeast fighting enzyme, while pasturized milk contributes to fungus because the enzyme has been destroyed. The gut yeast are then free to feed on the milk sugars.
Olive leaf extract , raw virgin coconut oil, Oregano oil, and caprylic acid are all good gut yeast fighters.
In good health,
Gail