Patients who have had weight loss surgery rarely have excess skin removed, although it can be such a bother for people who have shed a lot of weight that it has a negative impact on their quality of life, a poll said.

Plastic surgeons said patients either don't know about this extra surgery, called body contouring, or simply can't afford it - yet doctors say it's more than just a cosmetic procedure.

"It is surgery that improves patients' quality of life," said Jason Spector at Weill Cornell Medical College in New York City, to Reuters Health.

The excess skin that is left after severe weight loss can get in the way of exercising, interfere with patients' ability to wear clothes properly, and cause rashes and serious infections.

Spector said weight loss surgery, also called bariatric surgery, is just the first step.

"In order to complete the journey, patients really do need to undergo the appropriate post-bariatric body contouring. Even though that has a slightly cosmetic ring to it, it's certainly something that we, as plastic surgeons, would consider reconstructive," he added.

To get a sense of how many patients were actually going on to have body contouring surgery, Spector and his team mailed a survey to 1,158 patients whose operations were done by two surgeons between 2003 and 2011. They received 284 responses.

Only a quarter of the patients said they discussed body contouring with their surgeon around the time of the operation, with about 12 per cent actually undergoing the procedure, said Spector, who presented the findings at the annual meeting of the American Society of Plastic Surgeons.

The most frequent reasons for not having body contouring were expense and lack of awareness of the procedure. Nearly 30 per cent of the patients said they might have chosen differently if they had received more information.

The excess skin can pose a very real danger, Spector said. He described a patient whose overhanging skin was caught underneath the electronically controlled seat of her car as she was adjusting it.

"A large piece of skin was ripped off and caused a big open wound and subsequent infection. UP to that point, her insurance company had told her, 'sorry, you can't have the surgery. You don't need it.'"

According to Healthcare Blue Book, a consumer guide to healthcare costs in the United States, body contouring comes with a price tag of about US$13,000 (S$16,685).