I'm writing a drama story, and one of the main characters (a human girl of 8 years old) has an unusual weakness - she's allergic to H2O. She has to avoid water at all costs - for example in the story, one time she accidentally drunk a mouthful of water, and went into anaphylaxis, requiring adrenaline shots to reverse. She has to wear a special spacesuit like apparatus in case it rains as a single drop of rain will kill her, for example if she gets a single drop of rain in her mouth by accident, she will go into shock. She also has to avoid things like surgeries, her parents told the surgeons not to use any water on her as she's allergic and the surgeons took them seriously (in a world first - beforehand the surgeons always used water while operating on a patient), but after the surgery she had to be put on a medical drip (having water injected into her veins), and then went into anaphylaxis because the drip was water based. She hydrates herself by drinking 4 small glasses of milk or orange juice a day, which because of their chemical composition bring her no harm. She's 100% healthy as long as she avoids H2O as her immune system sees H2O molecules as foreign. She becomes famous in her country because of her allergy, stealing the hearts of residents near her. Another aspect to the story is she becomes a tragic hermit after a gang of cruel thieves break into her house and steal her 'spacesuit' and tear it up. She was born allergic, and while in her mother's womb she was kicking around a lot in pain. Does this story sound medically accurate? What would you rate it out of 10? The tone of the story is very serious and is meant to be taken seriously.
No. Human bodies are largely composed of water. Milk and orange juice are largely composed of water. This isn't possible. As a serious story, rather than a surreal/fairy tale story, I would rate it zero out of ten.
@ChickenFreak @Wreybies @Laurin Kelly Reality is unrealistic https://en.wikipedia.org/wiki/Aquagenic_urticaria Aquagenic urticaria, also known as water allergy and water urticaria, is a rarely diagnosed form of physical urticaria. The defining symptom is a painful skin reaction resulting from contact with water. It is sometimes described as an allergy, although it is not a true histamine-releasing allergic reaction like other forms of urticaria. I'm not sure how this would apply to some of the specific details @loverofcreations came up with, but the basic concept stands.
A skin reaction to water is interesting, but it seems only tangentially related to the original poster's concept--though it may explain what sparked the concept.
This makes no scientific sense. Is H2O even capable of being an antigen? I doubt it. Even the “allergy” cited above isn’t an allergy. Everything she drinks to stay hydrated is mostly H2O. She’s mostly H2O. To do this, you’d have to presuppose some massive chemical changes to her body that essentially make her something other than human. Then you could make it work.
I could imagine the possibility of imagining some sort of alien life that isn't water-based. Though it's a struggle.
Yes. Maybe ammonia-based. Maybe something that uses silicon instead of carbon? I don’t know. Water has some peculiar properties that make it suitable for life.
It's water with stuff dissolved in it. Could that 'fool' the immune system into not reacting to her own internal water? But her immune system reacts if she gets IV'd with water or drinks a mouthful of water.
No. There would have to be something in the water that she has an allergy to. It wouldn’t be an allergy to the water itself. Depending on how far you want to stretch things—maybe her own body water has some compound in it that she produces. A repressor or something, I don’t know. And when she gets an IV that gets diluted and whatever expression it is repressing gets turn on and that causes her an issue? I’m stretching here. A skin condition like the above I can see, but how are you going to have someone with an actual systemic allergic reaction to water and make it even somewhat plausible? What’s the mechanism? Why doesn’t the person die as soon as the allergy comes into being, probably at a very young age? You need a biochemical explanation for all of this if you want it to be realistic.
There is an actual condition (a rare one) where a person CAN be allergic to water. I recommend you look into it (sites like NCBI or rare diseases are sites I use or documentaries on the condition really help.) I'm not sure if your description of the illness is accurate, but heres what I found: https://rarediseases.info.nih.gov/diseases/10901/aquagenic-urticaria https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276800/ (Warning: very technical and the second link has images of the condition. Its kinda hard to look at)
@Simpson17866 mentioned this, too, but it's not actually an allergy, and it has very little similarity to what the poster is saying.
Sure--I was responding to your saying that a person can be allergic to water. The condition isn't an allergy.
You should research the science in this. Antigens, immune responses etc. And the fact that all of the reactions necessary take place in a “water” environment in the body. I think you’ll see quickly why an allergic response doesn’t make sense. Maybe you can come up with some other mechanism of action. The core idea, that her immune system sees a water molecule as foreign and that sets off an allergic response, is a non-starter.
Getting anaphylaxis from water is about as realistic as getting it from exposure to CO2 I'm afraid. A child actually has a higher water content than an adult, and what's more, it is the water vapour in our breath that is visible when we breathe out in cold conditions. Such a person would be dead from their first breath.
Would the concentration make the poison? For instance. let's assume we have someone deathly allergic to peanuts, but you grind up a single small peanut into a powder, and over the course of 24 hours, they ingest the powder extremely slowly. Would they still go into shock?
There is a sliding scale with allergies, but in some cases just breathing in minute traces in the air is enough to send someone into shock. This is why there is a debate about removing nuts from flights because the same air is being circulated around as part of the pressure system.