PALO ALTO, Calif. — Hewlett-Packard’s interim chairman Ralph Whitworth has resigned from the company’s board to concentrate on personal health issues.

Whitworth’s resignation is effective on Wednesday. Personal computer maker HP said that its board will discuss appointing a new chairman at its next meeting.

Whitworth became HP’s interim chairman in April 2013 after former chairman Ray Lane stepped down from his post. Whitworth, an activist shareholder, has served as an HP board member since 2011.

Whitworth is also taking a leave of absence from his investment company, Relational Investors.

Hewlett-Packard Co. is based in Palo Alto, California. Its stock slipped 2 cents to $34.13 in premarket trading Tuesday.