Split nails... how do I manage them?

My nails have been cracking and splitting lately, which is bothering me. I've been applying hand cream regularly, but it hasn't really helped. I'm wondering if I should be using more cuticle oil or moisturizer, or if it could be due to a lack of nutrition. If anyone has experienced similar issues, please share your experience and how you've improved them. I'd also like to know if I need to see a dermatologist.