Nutrient Deficiency Question

Every few months my right hand thumb and forefinger develop deep cracks (painful), is this caused by a certain vitamin deficiency?

I know this is a late response, but this is most likely due to dry skin. You can try one of two solutions: moisturize from the outside using lotions, or moisturize from the inside by adding slightly more fat to your diet, specifically monounsaturated and vitamin E.