Joshua Rutter, known as Josh, is white, 5ft 7in, with brown hair and blue eyes, police said.
A 41-year-old woman, known to Rutter, suffered cuts and bruising injuries at an address in Arundel Road, Littlehampton, on Wednesday (June 6), police said.
Rutter is frequently in West Sussex but also has associations with Guildford and Walton-on-Thames in Surrey, police added.
Detective Constable Lauren Ifould, of the West Sussex Safeguarding Investigations Unit, added: “If you know where Josh Rutter is, or where he has been since the incident on Wednesday, do not approach him, but let us know right away on 101, quoting Sussex serial 594 of 06/06. But if you see him, dial 999.”