[lilurchin (OP)]

I read an old short-story about a girl (the title of the story/book was ''Just One Cup of Water could Kill Little Heidi'') who would go into anaphylaxis if she got even a teeny drop of water in her mouth (requiring adrenaline shots to save her life) as her immune system saw H2O molecules as foreign and she was born this way. For example early on in the story she accidentally drank a mouthful of water and almost died.

The story said she once had surgery and was given a drip afterwards, and went into shock because the drip was ''water based'' and she was getting water injected into her veins.

She had to wear a spacesuit like contraption to avoid breathing in the water vapor (H2O molecules) in the air as that could instantly kill her since her immune system saw H2O molecules as foreign if she got any of them inside of her body.

So I Googled ''IgE antibodies against H2O'' or ''anaphylaxis to the H2O molecule being ingested'' and couldn't find anything. Closest thing I could find was skin irritation (called Aquagenic Urticaria), but not an allergy, upon contact with water. Anaphylaxis isn't a symptom of it though and doesn't match the girl's condition in the story.

[Bored chemist]

"Why can't I find any cases of anaphylaxis after drinking H2O"
Because water does not trigger anaphylaxis.

[lilurchin (OP)]

"Why can't I find any cases of anaphylaxis after drinking H2O"
Because water does not trigger anaphylaxis.

What if your mastocytes produced antbodies against H2O? For example the immune system can make mistakes and the body can essentially become allergic to itself which is what autoimmune diseases are.

This story is very popular in my country and several news websites have ran sequels and variations of it, while reporting it as if it were a genuine news story.

[Bored chemist]

What if your mastocytes produced antbodies against H2O?

Then you would die- immediately- because the whole of your body  is full of lots of water.

How could that not happen? What could stop it?

[lilurchin (OP)]

What if your mastocytes produced antbodies against H2O?

Then you would die- immediately- because the whole of your body  is full of lots of water.

How could that not happen? What could stop it?

I know the inside of cells are full of water but what about the outside? The antibody receptors on mastocytes aren't located inside the cell but outside of it, along its surface:

[Bored chemist]

I know the inside of cells are full of water but what about the outside?

https://en.wikipedia.org/wiki/Extracellular_fluid

[lilurchin (OP)]

I know the inside of cells are full of water but what about the outside?

https://en.wikipedia.org/wiki/Extracellular_fluid

Would this trigger anaphylaxis in a person allergic to H2O? For instance in the story the girl is perfectly healthy, until she gets a drop of water in her mouth or has water injected into her veins (medical saline drip)

[Bored chemist]

Psychosomatic?
I don't know what it is, but it obviously isn't water.

[Kryptid]

Would this trigger anaphylaxis in a person allergic to H2O?

Yes, as extracellular fluid is almost entirely water.

The story you mention sounds like it may have been invented. She would have to ingest water in some form or she would die from dehydration quickly.

[lilurchin (OP)]

Would this trigger anaphylaxis in a person allergic to H2O?

Yes, as extracellular fluid is almost entirely water.

The story you mention sounds like it may have been invented. She would have to ingest water in some form or she would die from dehydration quickly.

The sources were Daily Mirror, The Independant (UK) and Birmingham Mail
The original story took place in the 90's but there's later versions of the story where she's an adult.

Here's the original though -

https://www.thefreelibrary.com/JUST+ONE+CUP+OF+WATER+COULD+KILL+LITTLE+HEIDI%3B+Girl%27s+deadly+allergy...-a061152595

Although 'Aquagenic Urticaria' is mentioned the writer hasn't done their research on the condition as Aquagenic Urticaria is a harmless (yet irritating) skin condition. Not an allergy and anaphylaxis upon drinking water is not a symptom. https://en.wikipedia.org/wiki/Aquagenic_urticaria

[Kryptid]

The sources were Daily Mirror, The Independant (UK) and Birmingham Mail
The original story took place in the 90's but there's later versions of the story where she's an adult.

Here's the original though -

https://www.thefreelibrary.com/JUST+ONE+CUP+OF+WATER+COULD+KILL+LITTLE+HEIDI%3B+Girl%27s+deadly+allergy...-a061152595

Although 'Aquagenic Urticaria' is mentioned the writer hasn't done their research on the condition as Aquagenic Urticaria is a harmless (yet irritating) skin condition. Not an allergy and anaphylaxis upon drinking water is not a symptom. https://en.wikipedia.org/wiki/Aquagenic_urticaria

Whatever this is, it can't be typical allergies as her own bodily fluids would kill her (as stated before).

[lilurchin (OP)]

The sources were Daily Mirror, The Independant (UK) and Birmingham Mail
The original story took place in the 90's but there's later versions of the story where she's an adult.

Here's the original though -

https://www.thefreelibrary.com/JUST+ONE+CUP+OF+WATER+COULD+KILL+LITTLE+HEIDI%3B+Girl%27s+deadly+allergy...-a061152595

Although 'Aquagenic Urticaria' is mentioned the writer hasn't done their research on the condition as Aquagenic Urticaria is a harmless (yet irritating) skin condition. Not an allergy and anaphylaxis upon drinking water is not a symptom. https://en.wikipedia.org/wiki/Aquagenic_urticaria

Whatever this is, it can't be typical allergies as her own bodily fluids would kill her (as stated before).

Does anaphylaxis require a certain concentration of allergen or is it an ''all or nothing'' thing where a couple of cells get stimulated and then it sets off a nuclear chain reaction?

Also I'm pretty sure (mature) mast cells aren't located in the blood. But they're concentrated in connective tissues and mucosal tissues.https://en.wikipedia.org/wiki/Mast_cell

[Bored chemist]

Also I'm pretty sure (mature) mast cells aren't located in the blood.

It doesn't matter. The whole body is essentially water

[lilurchin (OP)]

Also I'm pretty sure (mature) mast cells aren't located in the blood.

It doesn't matter. The whole body is essentially water

Are there any images to demonstrate this? For example another poster said cells are bathed in water and there's always water between every cell but is this enough water to cause an allergic reaction?

[Bored chemist]

is this enough water to cause an allergic reaction?

Do you have any idea how small a quantity of material is needed to trigger an allergic reaction?

[lilurchin (OP)]

is this enough water to cause an allergic reaction?

Do you have any idea how small a quantity of material is needed to trigger an allergic reaction?

Not really...care to elaborate on that?

[Bored chemist]

The allergic reaction is a "misfire" of the immune system which has to be able to respond (n principle) to a single bacterium.
People will go into anaphlactic shock when exposed to quantities of material that are practically undetectable by other means.

[lilurchin (OP)]

The allergic reaction is a "misfire" of the immune system which has to be able to respond (n principle) to a single bacterium.
People will go into anaphlactic shock when exposed to quantities of material that are practically undetectable by other means.

Source? Roughly what concentration is needed? And since water is a small molecule, what if the receptors only responded to say 100 water molecules at a time around the receptor?

[Kryptid]

Not really...care to elaborate on that?

According to the diagram on the Wikipedia article posted earlier, 34% of the body's water is in extracellular fluid. Since the mass of the human body is 45-75% water, that would mean that a 65 kilogram person contains between 10 and 17 kilograms of water in their extracellular fluid. How do you think the human body would react to 10 kilograms of an allergen inside of it?

And since water is a small molecule, what if the receptors only responded to say 100 water molecules at a time around the receptor?

Given that even a trillionth of a gram of water contains over thirty-three billion water molecules, there would be far more than enough to stimulate those receptors in even a highly impure solution.

[lilurchin (OP)]

Not really...care to elaborate on that?

According to the diagram on the Wikipedia article posted earlier, 34% of the body's water is in extracellular fluid. Since the mass of the human body is 45-75% water, that would mean that a 65 kilogram person contains between 10 and 17 kilograms of water in their extracellular fluid. How do you think the human body would react to 10 kilograms of an allergen inside of it?

And since water is a small molecule, what if the receptors only responded to say 100 water molecules at a time around the receptor?

Given that even a trillionth of a gram of water contains over thirty-three billion water molecules, there would be far more than enough to stimulate those receptors in even a highly impure solution.

I see.
So what are your thoughts on this? https://www.thefreelibrary.com/JUST+ONE+CUP+OF+WATER+COULD+KILL+LITTLE+HEIDI%3B+Girl%27s+deadly+allergy...-a061152595

Is it some satire like the Onion?