I've literally tried everything under the sun. However, let me start with saying that I have very badly dry hands and feet.
My hands get so bad that the crease where the first joint of the index and little fingers tend to crack incredibly deeply and the skin in between my knuckles of my index and middle fingers on my actual hands (not fingers) crack deeply as well. These cracks, when they happen, get incredibly sore and can bleed.
I've tried baby oil, coconut oil, coconut cream, other creams and lotions for severely dry/cracked hands...I've even tried O'Keeffe's Working Hands cream. Everything. Most didn't touch my hands and the ones that did, like the Working Hands cream, seem to only work for a while and then stop.
I'm so tired of this severely dry skin and cracked fingers, knuckles and feet. Is there anything out there that can help?

have you considered going to a dermatologist (if you are able to)? You may need something prescription strength to help your hands/feet :( If you aren't able to go to the dermatologist, have you tried anything with lanolin in it? I've also heard great things about Soap & Glory's Heel Genius but haven't tried it myself. (A friend recently bought 3 tubes as backup!) If you're in the US and near a Sephora you may be able to get a discounted tube, I believe they're no longer carrying them so they've put the brand on clearance. Sadly it's no longer available on the website.
I've heard of lanolin but not for skin care. I'll look into that as well as the other cream. We have a Sephora here in my city in Canada so I'll call them tomorrow and ask!

For lanolin, I know Dr. Lipp's Nipple Balm for Lips (but it's not just for lips so it's such a weird product name) is quite popular but it's also pricy - considering it's 100% lanolin I would say you could definitely find a cheaper (and equally effective) alternative.
Also, reading the S&G heel genius page reminded me - have you tried putting on a thick moisturizer on your hands/feet before going to bed and then putting on a pair of thick gloves/socks so you can let it soak in overnight?
Have you considered trying some kind of vitamin/supplement? I'm having trouble finding any reputable source online (there are so many bad ones tbh) but I know some people swear by nutritional supplements for hair/nails. Maybe you could call your doctor or if that's not possible talk to a pharmacist (they definitely know their stuff too and will talk to you for free).
[flower=Marjolaine]
It's possible that you might have eczema. Like someone else said, a dermatologist might be able to help more. But as someone with eczema I feel your pain! I would recommend either Eucerin lotion or there's an eczema lotion actually made by Neosporin. They sell it at the drugstore, but I'm not sure if you can get it in Canada.
If all else fails, just slathering your hands in vaseline at night can help tremendously! Also, no matter what you put on your hands at night, wearing gloves/socks while you sleep is supposed to help too! Additionally, maybe try getting a small humidifier - sometimes the extra moisture in the air can help your skin.
Best of luck getting it figured out, I know how awful this feels. :/
I too thought of Eczema or dermatitis, by the severity of your hands I would go to your doctors to be certain. I'm no doctor but a workmate with psoriasis has uv light treatments. Eczema is helped a very bland emollient cream to keep the skin supple. It may be that you are allergic to something, the latex in rubber gloves for example? My facial skin is very sensitive,I have been told that once your skin is sensitive, then anything you put on it can upset it,please be careful when trying a lot of different things. I hope you get some relief very soon.
Ugh Dry skin sucks so much doesn't it? I get it in little circle patches on my face, and sometimes it explodes all over my face when I'm stressed haha. Here's some more suggestions for you to try, don't know if you'd have these exact products where you live, but maybe something similar?? Also definitely see a dermatologist if you can, they would be the best ones to tell you what to use especially if some stuff doesn't work, or half works or makes it worse etc..
Suggestions: Fatty Cream, An Oil-in-Water Emulsion Cream (that's what its called here in NZ, funny name huh) Ingredients: White soft paraffin, cetostearyl alcohol, liquid paraffin, cetomacrogol emulsifying wax, sodium citrate anhydrous, citric acid anhydrous, methyl parahydroxybenzoate, deionised water ===This one I use little like a moisturizer, but I don't use daily. I find the more I use creams etc the worse my skin gets, so I keep the use to a minimum==
Sudocrem, Cream for a bunch of different stuff (nappy rash, eczema, abrasions etc) Ingredients: Excipients, Zinc oxide, Hypoallergenic Lanolin, Benzyl Benzoate, Benzyl Alcohol, Benzyl Cinnamate ==This one I use less, cause its like thicker or something.. Ahh It works about the same as fatty cream, its just a thicker cream and has smell that I associate with nappy rash creams haha==
Locoid Lipocream, A hydrocortisone cream (hydrocortisone butyrate) Ingredients: hydrocortisone butyrate, cetostearyl alcohol, ceteth-20, mineral oil, white petrolatum, citric acid, sodium citrate, propylparaben and butylparaben (preservatives) and water. ==This one was specifically prescribed by my GP, and as I've always heard that you shouldn't use hydrocortisone in large amounts I only use this one when my skin reeeaaaallllyy bad. I'd say its the one that works best for me, but sometimes it does leave my skin feeling 'Tight'==
Dont know if any of that gibber helped, but I tried haha. Another thing I'd suggest to maybe change up your normal shower products. Like if you have a prefered body wash or soap, maybe try something else? Here in NZ we have a soap brand called Protex and it was recommended to me by my GP cause I have sensitive skin, and I've found that after I started using it my skin is nicer all over..plus Protex is a more 'hard out' anti-germ and anti-bacterial Soap so yeah.. /end of gibbering
Have You ever tried eating a dose Of aloe Vera supplement? Maybe your body needs to humidfy from inside while the creams Only do IT from outside. I have a friend who have dry skin problems and she says IT really helped. Myself i have never tried IT as i got ezcema and i wanted to test out a special cream first

There's a deep oily repair cream from the brand CV Skin Labs that contains Lanolin and is AMAZING. Pretty pricy but worth it. However, like other posters have pointed out..it does sound more like a very aggravated form of Dermatitis. Going to a Dermatologist may be the only thing that can clear it up.
Oh, also drink TONS of water!!
Drinking more water helps. Dehydration increases the likelihood that your skin will be dry. Product wise, I use Neutrogena Oil-free Moisture and Burt's Bees Soothingly Sensitive Aloe and Buttermilk Lotion. The aloe and buttermilk lotion goes a long way. A nickel sized drop is usually more than enough for both my hands. My skin has definitely improved while using it. Try to go to a dermatologist though because skin that cracks that deep could have underlying issues.
I also suffer from extremely dry skin, and eczema in some areas. The only thing that has ever worked for me is First Aid Beauty's Ultra Repair Cream. They still it at Sephora and it is amazing. It also doesn't have that gross medicinal smell to it.