A 69-year-old man died in hospital after he was given antibiotics to treat an organ inflammation, causing him to have severe rashes, a coroner's court heard.

During yesterday's inquiry into the death of Mr Sathiavellu V. Muniandy on Jan 15, 2020, the court heard that the doctors were not aware of his allergy, which led to a life-threatening skin disorder that covered 70 per cent of his body in rashes.

Coroner Marvin Bay ruled the incident an "unfortunate medical misadventure" and said there was no foul play suspected. He said the allergies were not documented in the patient's medical records and the doctors were diligent in treating him.

The court heard that Mr Sathiavellu was a retiree with a medical history of chronic illnesses. Since 2015, he had suffered from a blood vessel disorder called granulomatosis with polyangiitis.

Investigations showed that he was taken to Ng Teng Fong General Hospital (NTFGH) on Dec 12, 2019, due to fever and vomiting, and was prescribed antibiotics, said the coroner.

He said the patient's daughter noted that Mr Sathiavellu's face was slightly swollen and that a nurse said this was a normal reaction to the medicine.

Mr Sathiavellu's health worsened over the week and he returned to the hospital with fever again. He later developed mild rashes, swollen legs and his lips started to peel, said the coroner, based on the daughter's reports.

During hospitalisation, he was given high doses of antibiotics, known as dapsone and piptazo, up till Jan 2, 2020, when he was transferred to the intensive care unit as his condition deteriorated.

Citing a forensics expert who looked into the case, Coroner Bay said the antibiotics given were mandated to prevent infections from the steroids the patient was given to prevent inflammation during treatment.

But despite the stoppage of antibiotics, Mr Sathiavellu soon fell into critical condition and died on Jan 15, said the coroner.

The forensics expert said his death was likely due to multi-organ failure due to the skin disorder, which was aggravated by his chronic issues.

No doctor was aware at the time that he was allergic to the medication used, said Coroner Bay, adding that NTFGH doctors would routinely review patients' allergy records that are archived for all healthcare institutions.

The coroner said: "The system ensured that whenever a medication was prescribed, there would be a prompt to alert if the patient was allergic to that medication."