A man's death from anaphylactic shock could have been prevented by better communication processes around allergies, and health authorities have been asked to apologise to his family.

The man was treated for an injury while on holiday in 2019 and later died of anaphylaxis, in spite of the allergy being evident in a previous visit within his home DHB, Hutt Valley, three weeks earlier.

He died shortly after being treated intravenously with flucloxacillin.

In a report released today, New Zealand's health system watchdog the Health and Disability Commissioner (HDC) found HVDHB to be in breach the Code of Health and Disability Services Consumers' Rights for inadequate systems to ensure the allergy was recorded on the National Medical Warning System, and flagged with his usual GP.

The Deputy Commissioner heard the man was taken to Hutt Valley DHB by ambulance with a suspected allergic reaction in 2019.

He was discharged with a possible allergy to flucloxacillin, but the information was not recorded on a database, and the level of the detail provided to the man himself is unclear.

The man was on holiday three weeks later when he presented to a different DHB where he was given intravenous flucloxacillin, and sadly died of anaphylactic shock shortly afterwards.

While the man was asked whether he had allergies, he told staff he did not, and there was no alert on the national Medical Warning System of any possible allergies.

Deputy Health and Disability Commissioner Dr Vanessa Caldwell said the National Medical Warning System is designed to warn services of known risk factors that may be important when making clinical decisions about patient care.

"The purpose of the Medical Warning System is to warn health and disability support services of any known risk factors such as allergies that may be important when making clinical decisions about individual patient care," Caldwell said.

"The system has been linked to patient National Health Index numbers so that these alerts can be accessed and viewed throughout New Zealand."

"The responsibility for maintaining the content of the Medical Warning System rests primarily with healthcare providers."

She said there was inconsistency in the way warnings were managed, with each DHB adopting its own processes around what notifications could be added and by whom.

Weaknesses within the national system undoubtedly contributed to this event, she said.

"I nonetheless consider it vital for individual medical centres and DHBs to have their own adequate systems and processes in place for drug and medication allergies, to ensure that staff are supported adequately in their decision-making and reporting requirements."

The Deputy Commissioner found the DHB in breach of Right 4 (5) of the Code for having an inadequate system for ensuring that allergies were recorded and flagged, and for failing to communicate it with the man's usual general practice.

The Deputy Commissioner recommended the DHB develop an "end-to-end" process for the ED and general hospital setting, for when a patient presents with a new drug allergy, and considered designing and implementing a new discharge form.

She also recommended improved education for staff and intermittent audits of the adequacy of the processes.

Hutt Valley was also asked to provide a written apology to the man's family.