Currently my text area input (which accepts custom CSS input from a user) in the Wordpress theme options panel are sanitized by esc_html function in Wordpress http://codex.wordpress.org/Function_Reference/esc_html
However I am thinking a secure approach, so I would like to add HTML purifier and CSSTidy like it's illustrated here: http://stackoverflow.com/questions/3241616/sanitize-user-defined-css-in-php
Is this necessary? Or Wordpress core function like esc_html already uses HTML purifier so this is not anymore needed. Please advise. Thanks.