I have a itcy rash on my neck and the top of my hands. Why?

Allergy? An itching rash can be a number of things but considering its locations might be from something you came in contact with. Less likely, but still possible, is eczema which is another form of itching rash. People who have asthma and/or seasonal allergies are more prone to eczema. Keep an eye out for possible triggers to help differentiate the cause of the rash: detergent, pets, poison ivy, etc.