Schools are "not aware" of the need to offer allergy lessons to children, the mother of a boy with a potentially fatal allergy has said.
Stephanie Hulme's son William, six, could suffer a fatal anaphylactic shock from his allergy to cats and nuts.
Mrs Hulme, of Cardiff, is giving free allergy lessons in primary schools with the Anaphylaxis Campaign.
The Welsh Government said all schools have guidance to support learners with these healthcare needs.
Mrs Hulme said William was "sad and upset" when he could not join in some school activities such as bake sales.
But since his mother gave an allergy lesson, William said he "doesn't feel different" anymore.
In 2017-18, 255 people were admitted to hospital for allergies, according to Stats Wales.
The biggest hurdle for Mrs Hulme is getting schools on board.
She said: "The attitude of some schools is that if there is no child with allergies at the school – then why educate them?
"They aren't aware of the need to make all children aware of what allergies are."
In the lessons, Mrs Hulme explains what allergies are and how to spot signs of a reaction.
The Anaphylaxis Campaign has e-mailed more than 100 schools in south Wales, but said it had no interest in its free awareness sessions.
CEO Lynne Regent said: "We consider work with schools to be vital because it ensures that children in their care are safe.
"Part of the issue is that children with severe allergies look perfectly healthy – not 'ill' – but their lives could be in danger."
One reason behind the lessons is to help others not mistake an anaphylactic shock for something less serious, said Mrs Hulme.
Three years ago she failed to recognise William was having an anaphylactic shock after drinking a Starbucks smoothie in Canada.
William's lips became red, he started to "fall asleep" and hives appeared on his body because of a trace of flax seed in the drink.
Mrs Hulme said they had "no idea what this meant" until they rushed him to a hospital, where he got a life-saving EpiPen injection.
Since moving from Canada, the family have found it a "huge learning curve" finding the right foods and adapting to William's needs.
They are concerned about the EpiPen shortage in the UK and the rise of allergy-related deaths across the world.
"It is still a huge fear for us because food brands can change their manufacturers suddenly without any notification – and a favourite food can become potentially fatal.
"We all have a daily battle of checking every manufacturing method before buying anything," Mrs Hulme said.
A Welsh Government spokesman said: "Our officials have met with Mrs Hulme to discuss the presentation she has developed and are working with her to share this with all schools in Wales through our Dysg newsletter."