"Nurse has 100 orgasms a day", blurts a 2012 headline in the Sun. It reads more like the title of a film on YouPorn than the start of an article about a debilitating medical condition.

Underneath is a picture of Kim Ramsey, a 46-year-old British woman who has lived with the incurable illness known as Persistent Genital Arousal Disorder (PGAD) for six years. More often than not, PGAD sufferers are treated as hypersexual oddities. From the Daily Mail's "I climax every 30 seconds" to the Mirror's "I have 100 orgasms a day!", women with PGAD are repeatedly and incorrectly labelled nymphomaniacs.

But PGAD actually has very little to do with orgasms, and absolutely nothing to do with pleasure. The condition, largely suffered by women, is characterised by an implacable feeling of genital congestion and pelvic pain. Those who have it often feel permanently on the verge of an orgasm that they can't complete – a sort of chronic clitoral constipation.

"It feels like you're out of control," says Ramsey, who describes her experience of PGAD as a corporeal rollercoaster ride. "The more you panic, the more you get dragged kicking and screaming," she says, referring to the fear induced by a public flare-up of symptoms. PGAD sufferers soon learn to avoid triggers. Anything from a bumpy train ride, to inserting a tampon, to wearing stilettos (which offset the balance of the pelvis) can exacerbate the extreme genital sensitivity.

Ramsey, an A&E nurse who has lots of medical knowledge about her condition, explains that PGAD can be experienced differently from person to person. Some have constant arousal, but no orgasms. Others have multiple orgasms, which only provide a very superficial and short-lived sort of relief. "Everybody gets pain," says Ramsey. That's the one thing that all PGAD sufferers share. Ramsey, who chose not to take medication that would make her drowsy, self-medicates with distraction. At first, she tried placing all of her focus on her job, and worked solidly for a month. "It worked," she says, "but I still woke up in the night with symptoms."

"People hear orgasm and they think it's a good thing," says Kellie, a 33-year-old Canadian with PGAD. "Being on the edge of an orgasm 24 hours a day, to the point where you can't sleep, you can't function, you can't even think straight – that's not fun." For many PGAD sufferers, the urge to masturbate is overwhelming. But both Ramsey and Kellie explain that this can greatly intensify symptoms. Kellie says that she avoids masturbation at all costs. She is undergoing cognitive behavioural therapy, and finds that activities such as mindfulness meditation and swimming help to keep her calm. But the underlying symptoms are unavoidable.

"People think we have great sex lives," says Kellie, who has had the condition for a year, "but PGAD has ruined mine. My husband and I used to have great sex. We hardly have any at all now, because he doesn't want to add to my discomfort. I wish I didn't even have a vagina any more." For Kellie, who has two small children, stress causes flare-ups of her symptoms. Her doctor prescribed her Gabapentin, a drug that eases nerve pain and was originally developed to treat epilepsy. The medication helps her to cope with PGAD, but it doesn't relieve the symptoms entirely. "I'm not cured by any means," she says. "I'll probably have this for ever."

Jenny, a 59-year-old British woman with PGAD, says that, initially, the condition left her feeling as if her brain had moved into her vagina. "My sense of self went from my head to my genitals," she says, "I felt like I existed there. It was the scariest thing I've ever experienced."

Rebecca, a 66-year-old American who has lived with PGAD for around twelve years, says that she initially tried out a number of methods to numb her vagina. She used everything from ice-filled condoms to a strong anaesthetic ointment that put her in hospital with genital blistering. Now, she has found a great deal of relief through the use of a transcutaneous electrical nerve stimulation (Tens) machine. This device, commonly used to treat back pain, sends small pulses of electricity into the base of the spinal column. Since using Tens, prescribed by her doctor, Rebecca says that she's been practically PGAD-free.

The Sun's story about Kim Ramsey from August 2012. 'It was a sensational, ugly article,' says Ramsey. Photograph: The Sun

Jenny and Rebecca's PGAD started when they reached menopause, but the direct causes of the condition are unknown. According to a recent report by Dr David Goldmeier, a specialist in sexual medicine at St Mary's Hospital in London, PGAD is related to a number of conditions, from compression of the pudendal nerve (the one that carries sensation around the genitalia) to pre-existing mental health problems; namely anxiety and depression.

But Ramsey's PGAD began with lower back pain caused by a fall. "This isn't in my head," she says. "It's a neurological disorder that isn't getting the appropriate attention." Goldmeier's report also mentions the correlation between PGAD and the use of SSRI antidepressants. Kellie noticed symptoms as soon as she began a course of antidepressants. She came off the medication immediately, then found herself suffering from restless leg syndrome and an overactive bladder. Both of these conditions are related to PGAD. Like Kellie, Rebecca, abruptly came off SSRIs before she became ill. Rebecca has now lived with PGAD for around 12 years.

A standard medication for PGAD doesn't exist. The condition is treated with everything from anti-neuralgic medicine usually prescribed for Parkinson's disease, to, in some cases, Botox injections. The symptoms can be calmed, but not cured, and the permanent frustration can have severe effects on mental health.

In 2012, two women with PGAD, one in the US and one in the Netherlands, killed themselves. Gretchen Molannen from Florida, who was a member of the same online support group as Ramsey, was 39 when she took her life. She had lived with PGAD for 16 years. Ramsey, who never actually met Molannen but had emailed with her, and other group members contributed to the cost of her funeral.

Ramsey says that the two deaths had a profound effect on her and many of her fellow PGAD sufferers. They realised just how destructive the illness can be when the right help isn't available. With such little research into the condition and the media so often treating women with PGAD as freaks of nature, this is regularly the case.

Ramsey, who shared her story with the Sun in the hope of raising awareness of the condition, was understandably furious when she saw the lurid headline. What's more, the article had been cut down to a few sentences, focusing almost entirely on her persistent orgasms, and far removed from the context of PGAD as an illness. "It was a sensational, ugly article," says Ramsey. She raised the issue with the Press Complaints Commission, and her complaint was upheld.

But Ramsey had already, reluctantly perhaps, become a kind of poster girl for PGAD. Having emigrated to the US, she became a regular fixture in the American media when it came to stories about the illness. At one point, she had reporters showing up at her door and her name was quoted by journalists who hadn't even bothered to talk to her. All of the women I spoke to about their experiences with PGAD were concerned, first and foremost, that I would treat their stories with sensitivity.

"We don't get handled like humans," says Ramsey. "Nobody wants to be labelled a slut; those sorts of stains are indelible." In terms of "embarrassing" illnesses, a woman with persistent arousal is about as taboo as they come, and shame has come to play an enormous part in PGAD. According to Goldmeier, the condition is likely to be rare. In a survey of 100 women he carried out in a sexual health clinic, only one had PGAD. But, because of the stigma attached to the illness, it's hard to know how many women are living with it and are too afraid or ashamed to seek medical attention. When Ramsey began to appear in the media in stories about PGAD, many acquaintances stopped speaking to her. "[As a black woman] I thought the black community in America would accept me," she says, "Absolutely not. I got shunned all over the place. I know what it's like to be a leper."

Similarly, Kellie feels that she can't discuss her PGAD with friends. "I have to pretend I have a bladder problem," she says, "I call it my 'bladder issue'." What's more, even doctors can't be relied on for those with the condition. "Some doctors don't even know what it is," says Kellie, "I had to search hard to find one who did."When she first saw a doctor about her PGAD, she was treated like a fantasist. "I was crying and needing help," she says, "But he just looked at me like I was making it up."

Ramsey feels that the sexual health industry focuses on other problems, such as erectile dysfunction and inability to reach orgasm, while PGAD is largely ignored. "Good girls don't talk about sex," she jokes, bitterly. For this reason, she's a member of the American Association of Sexual Educators, Counsellors and Therapists (Aasect), and is hoping to educate people about PGAD. Women with the condition are often forced to be their own advocates, and she wants to help them. In the meantime? Ramsey quotes Winston Churchill: "If you're going through hell, keep going."