Hanna Scigala, 31, died on January 7, two days after going into catastrophic anaphylactic shock.

The single mother from Maryland has left behind three children - Madden, 12, Leo, 9, and Peyton, 3 - who are now under the care of their grandparents.

Hanna's sister Steph Scigala has organised an online fundraiser to help set-up the three children with their grandparents - the grandfather is retired and grandmother works only part time.

The money will also cover the cost of a memorial.

The family is still struggling with how exactly the anaphylactic attack took place.

Hanna had long known of her allergy to peanuts and family and friends went to great lengths to ensure she was never exposed to them.

"She was always cautious with what she ate," Steph told the Newcastle Herald yesterday.

"No-one in the family kept anything with peanuts in their house because even if they were to eat it prior to her coming over and they kissed her on the cheek, for example, she would flare up.

"We have no idea what she ate to cause the reaction.

"Given the time [between 9pm and 9.30pm] at night we assume it was something sweet."

Steph said her sister was dedicated to her family and job - she recently started a small cleaning business and had many clients who considered her a friend.

She had a love of interior design - furniture and decor was always changing at her Maryland home - and she loved a walk with her kids and their dog Bruno.

Steph said Hanna was "free-spirited" and had a good sense of humour.

"You could never take her seriously," she said.

"She had one of the most kind hearts and would do anything for anyone. She continues to do so ... as an organ donor."

The fundraising page, titled 'Help 3 children who lost their mum' is live on the Go Fund Me website.