The case of a boy who died from an allergic reaction after cheese was thrown on him is "unprecedented", a medical specialist has told a British inquest.

Karanbir Cheema collapsed at his school after the incident in London on June 28th 2017.

The 13-year-old had multiple allergies - including to dairy, wheat, gluten, egg, milk and tree nuts.

He was taken to hospital in a life-threatening condition but died almost two weeks later with his parents by his side.

Dr Adam Fox, a paediatric allergy consultant, told the inquest into his death: "Where this case is extraordinarily unusual is the nature of the event that led to the anaphylaxis.

"Because severe allergic reactions through skin contact are very, very uncommon indeed, and if it was skin contact alone that caused, in this case fatal, anaphylaxis, I believe that to be unprecedented.

"I have been unable to find any case reports. I've canvassed widely around this and I'm not aware of any fatal cases."

St Pancras Coroner's Court heard that there had been other cases of children having severe allergic reactions through skin contact, but none of these incidents were fatal.

The teenager who threw the cheese that landed on Karanbir's neck has told the inquest that he was only "playing around" - and said he had thought his classmate was only allergic to bread.

Karanbir also suffered from eczema, and the inquest was told that he scratched at his neck so much that blood was visible following the incident.

"Further scratching and degrading of the skin barrier could have led to further contact," Dr Fox explained.

Out-of-date Epipen

The inquest also heard that his Epipen was 11 months out of date and was the only adrenaline administered before he went into cardiac arrest.

He had displayed signs of anaphylaxis for several minutes before he received the adrenaline - prompting Dr Fox to warn that it is crucial to get the adrenaline out at the first sign of an allergic reaction.

Coroner Mary Hassell described the response of a senior paramedic in treating the teenager as "panicked".

Alexandra Ulrich from the London Ambulance Service (LAS) said that Karanbir's symptoms seemed to be consistent with a severe asthma attack - and she could not see any rash, hives or swelling.

The experienced paramedic gave Karanbir two grams of magnesium sulfate, which is used to treat muscle spasms during severe asthma attacks but is not meant for under 18s.

"If I had known about the specific details of the history about the allergens, I wouldn't have given it," Ms Ulrich said.

The coroner replied: "It just sounds like you were missing that few seconds to step back and say 'What do we have here?'

"Do you think you were influenced by the panic around you?"

Ms Ulrich responded: "Probably."

Andrew Jones, paediatric intensive care consultant at Great Ormond Street Hospital, said Karanbir's brain was severely deprived of oxygen.

The teenager was placed into an induced coma, but as the days progressed, he "eventually had no chance of survival".

Dr Jones said that Karanbir died after his parents agreed to gradually withdraw the drugs which were keeping him alive.

The trial continues.

Main image: A view of St Pancras Coroner's Court in London | Image: Anthony Devlin/PA Archive/PA Images