The development comes after 41 reports of possible anaphylaxis were detected in the UK, with likely links to the vaccination.
Severe allergic reaction is listed as 'not known' under possible side effects of the AstraZeneca jab published by Downing Street.
The European Medicines Agency, based in Amsterdam, said on Friday it had 'recommended an update to the product information to include anaphylaxis and hypersensitivity (allergic reactions) as side effects.'
They added: 'The update is based on a review of 41 reports of possible anaphylaxis seen among around 5 million vaccinations in the United Kingdom.
'After careful review of the data, (the committee) considered that a link to the vaccine was likely in at least some of these cases.'
A nurse vaccinates a man with the AstraZeneca Covid-19 vaccine during a mass vaccination campaign for people between ages of 50 to 55 in Vigo, northwestern Spain
The EMA added that anaphylaxis - or severe allergic reactions - was already a 'known side effect that may occur, very rarely, with vaccines.'
The product information for the jab says people should be kept under 'close observation for at least 15 minutes' after receiving the vaccine.
It comes after several countries paused use of the AstraZeneca jab following fears the vaccination could cause blood clots.
However, the World Health Organisation has insisted there is no link between the jab and an increased risk of developing the condition.
Some 5million Europeans have received the AstraZeneca vaccine, with around 30 cases of blood clots detected after it was administered.
Severe allergies should be added to the list of possible side effects of AstraZeneca's Covid-19 vaccination, the EU's drug regulator said
The EU is facing vaccine chaos after AstraZeneca announced a fresh shortfall in planned shipments as five European countries claim others are signing 'secret contracts' to make sure they get extra jabs
These cases are being investigated, but no casual relationship has been detected between the jab and the 'thromboembolic events.'
Yesterday, AstraZeneca dismissed concerns that its Covid-19 vaccine is linked to blood clots, joining the WHO, No 10 and EU regulators in rejecting the fears that have led several European countries to suspend their use of the jab.
The pharma giant said its analysis of more than 10million records showed there was 'no evidence of an increased risk' in any age group or any batch of doses, after Austria and others black-listed a particular shipment over fears of side-effects.
'In fact, the observed number of these types of events are significantly lower in those vaccinated than would be expected among the general population,' the firm said.
Austria, Bulgaria, Estonia, Latvia, Lithuania and Luxembourg have suspended one batch of doses after a 49-year-old nurse died soon after getting one of the jabs.
The EMA added that anaphylaxis - or severe allergic reactions - was already a 'known side effect that may occur, very rarely, with vaccines'
WHO spokeswoman Margaret Harris said: 'Yes, we should continue using the AstraZeneca vaccine. There is no indication to not use it.'
'AstraZeneca is an excellent vaccine, as are the other vaccines that are being used,' she said at a briefing in Geneva.'
Elsewhere today, AstraZeneca announced a fresh shortfall in planned shipments as five European countries claim others are signing 'secret contracts' to make sure they get extra jabs.
The pharmaceutical giant cited production problems and export restrictions as the cause for the delay.
The company had previously warned it was facing shortfalls from its European supply chain due to 'lower-than-expected output from the production process.'