A Western Australian teenager stung by one of the world's deadliest jellyfish has been released from hospital two weeks after the Easter Sunday incident.

Hannah Mitchell, 14, was swimming with a friend by Goodwin Island off the state's Pilbara coast when she felt a sting on her arm, but did not think much of it.

"It just felt like a normal jellyfish sting because we had been getting stung all day by sea lice," she said.

"But as we were swimming and walking along the sand my stomach started cramping. I thought it was hunger."

Minutes later and back on board a friend's boat, Hannah began to collapse in pain.

"I couldn't stand up. The top half of me was freezing," she said.

"I was screaming … I was in agony. It felt like my lungs and my heart were collapsing."

Along with excruciating pain and cramping, one of the more unusual symptoms from an irukandji sting is a sense of impending doom.

"In my head I was saying goodbye to people because I thought I was dying," Hannah said.

Hannah, with her mother Casey, says the sting felt like a normal jellyfish sting. ( Supplied: Casey Mitchell )

Labour pain 'times a million'

Hannah was rushed to the nearby Karratha hospital then airlifted to Perth by the Royal Flying Doctor Service.

Hannah's mother Casey Mitchell said to manage the pain, doctors placed her into an induced coma.

"It's quite sad for me to say, but when they put her to sleep the whole hospital and myself breathed a sigh of relief because she was finally out of pain," she said.

"Never as a parent have I ever thought I would say that, that I'm glad she's in a coma."

Hannah was in an induced coma for several days at Princess Margaret Hospital, but the pain returned once she was conscious.

"To bite the pillow to not upset the children on the ward as what can only described as severe contractions in labour pain but times a million … and I know the mums … will understand what I mean by that," Ms Mitchell said.

Hannah was discharged at the weekend but is still on medication to manage the pain.

Ms Mitchell said the family had been overwhelmed by support from the Karratha and Roebourne community.

"We nearly lost her from tiny little jellyfish … but she won and she's here."

Although small in size, irukandji jellyfish deliver a painful and potentially fatal sting. ( ABC Far North: Mark Rigby )

Little known about irukandji jellyfish in WA

James Cook University Institute for Tropical Health and Medicine associate professor Jamie Seymour said it was difficult to predict how people would react to irukandji jellyfish stings.

"The issue we have with irukandji stings is that we don't know enough about it," he said.

"One would expect that small children and elderly people should have a greater effect, but that doesn't seem to be the case.

"But the vast majority of people who do get stung by this animal and that have come in contact with it, all is going to result in them being in hospital in a truckload of pain."

There have only been two deaths recorded from irukandji jellyfish stings.