My wife has an itchy irritation in her belly button that began on february 13 2013. it itches. what could it be and how do we treat it?

Need more info: Common causes would include irritant or allergic problems to skin care products used on the skin. Questions to ask her are: has she changed skin care products recently such as moisture creams, soaps, etc. Has she had problems like this before? Does she have dry skin issues. Try some otc Hydrocortisone 1-2 weeks and if no help or especially if worsens, see your dermatologist.