On rare occasions that Medinah leaves her home, people around her will cough, sneeze and rub their eyes.

“I am the allergen,” the 23-year-old, who did not want her full name used, tells Sky News.

She is one of a group of people with a condition so rare it does not have an official medical name.

It is known simply as People Allergic To Me – often shortened to PATM.

Medinah spent a year online searching her symptoms before she found social media support groups and the name that had been coined there.

During those months, she worried she was “crazy”: “I thought, yes, I’m losing it now. But then after a year and the constant reactions with people, I just realised this cannot be in my head, I can’t be crazy, I’m seeing this in real time.”

Hay fever-type symptoms

Several of the people in those groups spoke to Sky News. They described people developing hay fever-type symptoms in their presence, saying as much as 90% of a room would start coughing, choking, or sneezing when they entered.

They detailed the immense toll of isolating themselves to avoid these reactions. Some said they had been suicidal; others talked of losing friends, giving up jobs, and spending hundreds of pounds on possible remedies.

Last year, PATM sufferers had a glimmer of hope. A researcher in Japan published the first cohort study on the condition – and it indicated there could be a physical cause.

Speaking to Sky News from Tokyo, Professor Yoshika Sekine from Tokai University describes what he found when he compared the skin gases emitted by 20 people with PATM to a control group of 24.

He discovered the PATM group had “very specific characteristic skin gas patterns”, giving off higher levels of certain chemicals that are known to provoke respiratory symptoms in people exposed to them.

One of them, toluene, is used in the manufacture of explosives, paints and plastics and as a solvent in some types of paint thinner and glue. It can cause irritation to the eyes, nose, throat and respiratory tract, according to Public Health England – and people with PATM emitted 39 times more of it than the control group.

The other chemicals Prof Sekine identified as being particularly important are sulphur compounds, which have a “very strong, pungent odour” and hexanol, which has a hay-like smell.

These chemicals are known to trigger respiratory symptoms and skin irritation and are both linked to sick building syndrome, a condition recognised by the World Health Organisation where people are made ill by the building in which they live or work.

The study concluded: “We must carefully consider the possibility that the chemicals emitted by the PATM group may induce chemical intolerance in those around them.”

‘You feel you don’t have the right to live’

It’s been about 18 months since Fahima started noticing reactions from people around her.

“Wherever I go, if I go into a shop, if I’m out, if I walk past someone, people will sneeze and hysterically cough,” she tells Sky News.

In that time, she’s shifted to working entirely from home. She has stopped attending her nine-year-old son’s school plays because “I don’t want to impact the children”.

She shops in the early, quiet hours. The school run is the only time she regularly leaves the house.

“From the minute I wake up, the first thought is, how are people going to react to me today? I have to minimise myself so that I don’t impact other people.”

She says she also gives off an odour that developed from sweat to fish and then faeces.

There is a medically recognised condition called trimethylaminuria (TMAU) – sometimes called “fish odour syndrome” for the smell sufferers emit – that is sometimes grouped together with PATM.

However, there are PATM sufferers who say their symptoms are not accompanied by any discernible smell.

Dr Robin Lachmann, one of the country’s leading doctors specialising in TMAU, tells Sky News that unlike PATM, TMAU is a condition “which we understand well and can treat”.

A key difference is that while people around the patient may find the odour unpleasant, “these responses aren’t allergic”.

Fahima took a test for TMAU which came back negative – but even getting the test took a year of “legwork” on her part, she says.

“With PATM, doctors say even if you want to get tested, there’s no diagnosis. There’s no way to treat it.”

The reactions Fahima gets aren’t just involuntary coughs and sneezes, she says, but insults and abuse.

“You know what? I don’t blame people. Especially the people that are having allergic reactions to us, we’re physically making them sick, so I don’t expect them to have any other reaction.”

But it’s “draining”, she says, and makes her “incredibly depressed”.

“It makes you feel like you don’t have the right to live, almost. Because why should you be in a place making someone else feel uncomfortable?”

Fahima says the allergic reactions vary depending on her diet. If she eats a lot of sugar, meat or carbohydrates, the following day she will notice a lot of people sneezing.

Her son mostly doesn’t react to her, she says, but when she eats meat his reactions are so severe she will give him an antihistamine.

Prof Sekine says while skin gases are typically influenced by diet, he hasn’t yet been able to find a link for PATM. But he has spoken to people who have improved their symptoms by cutting out dairy, increasing their intake of antioxidants and working on boosting good gut bacteria.

He also suggests why not everyone reacts to people with PATM. He says it could be to do with sensitivity to chemicals, with some people affected by very low doses in the air around them.

Just as not everyone suffers from hay fever when there’s a high pollen count, not everyone will be sensitive to the higher chemicals in the skin gases of PATM patients.

‘It’s all in your head’

The PATM sufferers who spoke to Sky News invariably said they had been told the condition was “all in their head”.

There is a recognised psychological condition that bears similarities to PATM called Olfactory Reference Disorder, or ORD.

People with ORD are preoccupied with the belief they are giving off a bad smell despite there being no odour, explains Professor David Veale, a consultant psychiatrist at the Nightingale Hospital.

It can have a “devastating” impact on peoples’ lives as they dedicate their energy to tackling the perceived problem and avoid social situations out of fear of being “shamed, humiliated, rejected”, he says.

“They are very stressed and very disabled by it. But no one can convince them that they can’t smell them. They think they’re just saying that to be nice.”

Prof Veale says the difference between PATM and ORD appears to be that ORD patients are preoccupied with their perceptions of what other people think about an imagined smell, while PATM sufferers perceive physical reactions in other people.

Prof Sekine also identifies this difference in his research, concluding PATM is unique “in that it affects the people around them, at least based on descriptions by people with PATM”.

Sandra, who did not want to use her real name, says she seriously considered whether her condition could “be in my head” after her doctor suggested she had ORD.

“I’d had too many incidents happen for that to be true,” she says.

“I was even bullied at work about it in one job.”

Almost 60, Sandra has lived with the condition for 15 years. She says she used to have a good career, but no longer works “partly due to the stress and anxiety that this causes”.

Her first sign of PATM came when she returned to work after a bout of sickness and her boss had a “sneezing fit” every time he came into her office.

A deep clean didn’t sort what she thought was a dust issue – and then she noticed other colleagues reacting in the same way, then friends and even her husband.

“Eventually it occurred to me that it must be me causing this, which filled me with horror,” she says.

“When the reactions are at their worst, I have a similar reaction myself, that is I become allergic to myself.

“I have other symptoms like a bad taste in my mouth, itchy throat, itchy skin with a mild rash on my abdomen and spiking mild temperature.”

But making others react is the worst part: “It makes me feel dreadfully guilty to be causing all of this and I have severe anxiety and depression as a result.”

Alex’s 24-year-old brother Miguel first noticed PATM symptoms about 10 years ago, but didn’t tell his family until he was 19.

Many people with PATM say close relatives do not get symptoms, and Alex does not notice himself reacting to his brother.

He says it’s also hard to say whether more people cough and sneeze around his brother because it’s such a commonplace thing – but Miguel will notice every cough or nose scratch, and someone having a coughing fit can be enough to make him stay in his room for days.

Alex recalls being at a restaurant with their grandparents when Miguel first told them about the condition, and his grandmother agreed she could hear people “just constantly coughing in the restaurant”.

“That seemed like an increase to what’s normal. But then how do you know what normal is if you’re not paying attention to it?”

PATM is easy to write off as “just” psychological because “it sounds ridiculous”, Alex says, but his first concern when his brother opened up about the condition was to find a way to cope with the impact on his mental health.

“That’s the important thing – and then it doesn’t matter whether it’s real or not.”

What causes PATM?

The cause of PATM is a puzzle to sufferers and researchers alike. Some people say their symptoms started during a time when they were eating a lot of fast food or experiencing high stress.

Sufferers trade theories about possible triggers: a disrupted gut microbiome, fungal infections, sinus problems.

“You’re like your own doctor, your own medical team,” Medinah says. “I literally stay up all night researching.”

Sandra and another person who spoke to Sky News found their PATM flared after a course of antibiotics, while others described developing skin issues before other symptoms.

MEBO Research, a small collective of researchers investigating rare genetic metabolic diseases, has conducted exploratory studies of PATM without being able to pinpoint a cause beyond an apparent issue with the body’s “detoxification process”.

Mehmet Ali, MEBO’s director of community outreach and strategy, tells Sky News PATM needs attention and research from the medical community.

Prof Sekine’s research also did not identify a cause – although it is his goal to find it. “I would like to define the criteria for what PATM is, and what it is not. This is a very difficult point,” he says.

Without even a criteria of what PATM is, there is no formal diagnosis. NHS England told Sky News it follows NICE guidelines, and there are none for PATM.

A spokesperson for NICE said it “can only look at treatments that are licensed by the UK regulators… If they have not been licensed for PATM, we cannot recommend them for the condition”.

But finding a treatment seems a distant dream to sufferers who share remedies on Facebook and Reddit: supplements of every variety, antibiotics, digestive enzymes, probiotics, herbal treatments.

Sufferers go to extreme lengths in search of solutions. Fasts; eliminating sugar, gluten and dairy; raw veganism and its opposite, the “carnivore diet” – essentially just eating meat, eggs and dairy.

But what might grant one person temporary relief doesn’t necessarily work for someone else.

Sandra sees no end to her 15 years of misery: “We are all just waiting for a cure with our lives in effect on hold but I’m nearly 60 now and not confident it will happen in my lifetime.”

‘It crushes you like nothing has crushed you before’

Amir, who did not want to use his real name, says without family relying on him “I wouldn’t be here, that’s how bad I feel sometimes”.

He describes a life that has become “really, really unbearable”. He says he has lost all his friends “because they can’t be in the same areas as me” and even avoids the mosque.

“I do an experiment – I stay out of the room to see if anyone is coughing, then go in the room for a few minutes. The majority of people will start reacting.”

Not everyone with PATM who spoke to Sky News isolates themselves. Some hold down jobs and socialise – but none seem immune to the mental health impacts of the condition.

They describe the loneliness of not just being physically isolated, but of being misunderstood by doctors, friends and family; the guilt of feeling you’re making another person ill; the despair of there being no treatment or cure.

Medinah describes her mental health as “shattered, it’s non-existent”.

“In the beginning it crushes you, it crushes you in a way that nothing has ever crushed you before.”

She says she quit her job as a teaching assistant because she was getting “aggressive” reactions, and now life is at a “complete stop”.

She gets emotional talking about the future: “I don’t feel excited at all. I don’t even like to think about it. The reality is so sad. I can’t even go to the local park, I can’t do anything.”

Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email jo@samaritans.org in the UK. In the US, call the Samaritans branch in your area or 1 (800) 273-TALK.