SINGAPORE - Singapore Airlines (SIA) said on Wednesday (July 19) it is reviewing the serving of nuts on board its flights, following an incident last week when a toddler had an allergic reaction to peanuts eaten by other passengers.

The three-year-old boy, Marcus, was with his parents Chris and Hong Daley on SQ217 from Singapore to Melbourne last Wednesday (July 12) when the incident occurred.

The Daleys, who are from Australia, have reportedly lodged a formal complaint with the airline.

They told the Australian Broadcasting Corporation (ABC) on Monday that Marcus was served a nut-free meal but had an allergic reaction after other passengers opened their packets of peanuts, which were served as a snack.

"He started vomiting, his eyes were starting to swell and he couldn't speak properly," claimed Mr Daley.

The situation was quickly brought under control with the Daleys' anti-allergy medication that they had brought with them. They said Marcus suffers from anaphylaxis, a severe allergic reaction that can typically be caused by certain food, medication, or insect bites and stings.

According to the Mayo Clinic, anaphylaxis is potentially life-threatening and can occur within seconds or minutes of exposure. It causes a person's immune system to release a flood of chemicals that can lead to one going into shock.

An SIA spokesman told The Straits Times on Wednesday that crew members immediately removed all packets of peanuts from the area around the family as soon as they were made aware of the situation.

The serving of peanuts was also suspended in the cabin for the remainder of the flight.

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"Currently, customers with nut allergies can request for a nut-free meal at the point of booking or at least 48 hours before their flight," the airline said.

"Following the incident, we are reviewing the serving of nuts on board our flights."

SIA has also reached out to the family and is in contact with them.

A family friend of the Daleys who was on the same flight complained on SIA's Facebook page that she also had a minor allergic reaction to the peanuts.

Ms Daley was quoted by ABC in its report that she felt the airline had dismissed their genuine concerns.

"We have just been brushed off and we just want to make people aware that this can happen on a plane," she said. "All they have to do is just stop serving peanuts… and there's so many snacks."

An all-out peanut ban on flights is not the norm for airlines worldwide. Among the major airlines, Emirates, Qatar Airways and Etihad Airways do not offer nut-free flights.

Australian airline Qantas reportedly stopped serving peanuts on flights in 2007. On its website, it says it has removed peanuts as a bar snack on all Qantas flights and from Qantas-owned and operated lounges.

Air New Zealand does not use peanuts, peanut products or derivatives of peanuts in its meals, but said on its website that it "cannot guarantee there are no trace elements of peanuts".

It said it does not serve peanuts as snacks in any class, but serves other nuts as a pre-dinner snack in Business Class.

SIA has an advisory page on its website which addresses the issue of passengers with nut allergy. On it, SIA said it is unable to provide a nut-free cabin or guarantee an allergy-free environment on board.

"It's not unusual for other passengers on our flights to be served meals and snacks containing nuts or their derivatives. We also have no control over passengers consuming their own snacks or meals on board, which may contain nuts or their derivatives," the advisory added.

"We request that you take every necessary precaution, bearing in mind the risk of exposure."

Meanwhile, some netizens backed the Daleys' subsequent request for all airlines to consider not serving peanuts on flights.

Marni Rosenberg Levin left a comment on SIA's page saying she considers the incident "negligence of the highest degree".

"As someone who suffers from peanut allergy myself, and as a doctor, I don't understand why you would knowingly put your passengers at risk," she wrote. "How can you prioritise someone's right to eat peanuts over the risk of a passenger dying from a fatal allergy on board a flight?"

However, some pointed out that the airline cannot stop other passengers from eating peanuts.

Sean Goh responded to Ms Levin saying: "They cannot prevent other passengers to bring nuts inclusive (of) snacks on board. It is time for you to consider other travel options."