Dear Dipali, unless it is too personal, you can share the real reason for which you were out of a job. There is no need to concoct reasons.
Your worry about skills getting outdated is a little unfounded. The service functions of the HR department, which were earlier called personnel management, have remained the same. Some changes in labor laws have taken place, and you can update yourself on these changes. The core part of HR has also remained the same. HR's role in this function lies in improving relations with employees or enhancing their engagement with the organization. It cannot become outdated in 2-3 years.
Therefore, go ahead and start applying for jobs. If you have an MBA or have completed a course in HR, then open your books and start reading. Refresh your knowledge!
All the best!
Dinesh Divekar