For Connor, an overwhelming desire to get to the nearest mirror is one of the first signs. “Usually, I would have already begun picking or scratching other parts on my body if I can’t control the urge,” he says. Connor, like many others, lives with compulsive skin picking: an irresistible urge to pick at or scratch one’s skin that can have disastrous effects on body and mind.

“When I begin picking, I completely zone out,” he says. The aftermath of a session can last for up to 45 minutes, the result not only of the sore, red skin on his face, but also the rush of “self-loathing and hatred” at what he has done to his appearance.

Skin-picking disorder, also referred to as excoriation disorder or dermatillomania, is believed to affect as many as one in 20 people. It is among a group of behaviours (along with trichotillomania – compulsive hair-pulling) known as body-focused repetitive behaviours (BFRBs) and was recently recognised as a distinct entity in psychiatric classification systems.

Those who struggle with this disorder might scratch, pick, rub or dig at their skin with their fingernails or sometimes tools such as tweezers, resulting in wounds, sores and, eventually, scarring. Dr Daniel Glass, a consultant dermatologist at the Dermatology Clinic in London, says patients’ skin “can be quite deeply damaged” by the behaviour and can present anything from one or two lesions to more than a hundred. The impacts can be psychological as well: “If we have problems with our skin, it may make us feel low and reluctant to face the world.”

Although it is growing, awareness of the condition is still fairly low. “These are disorders of shame and isolation,” explains the psychologist and BFRB expert Fred Penzel, who is based in New York. “That’s what keeps a lot of people from even seeking treatment – they’re afraid to reveal that they do this.”

After particularly bad incidences of skin picking, Connor has shunned social events, skipped gym sessions (which normally he loves) and hidden away in his room, he says. “I feel embarrassed by what I’ve done to myself.”

Common misconceptions about the disorder can make it very stigmatising, says Penzel, who is a founding member of the science advisory boards of the International OCD Foundation and the TLC [Trichotillomania Learning Center] Foundation for Body-Focused Repetitive Behaviors. Although it is classified as an “obsessive-compulsive and related disorder” in the fifth edition of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, the condition is considered different from obsessive-compulsive disorder, as it is neither self-harm nor necessarily driven by a deeper issue or unresolved trauma.

Although skin-picking disorder can appear at any age, the onset is often in childhood or adolescence. Connor, now 24, was at secondary school when he noticed how much more he picked at his skin compared with his friends: “I didn’t seem normal,” he says. Holly Davidson, 38, also recalls picking avidly at her skin as a teenager. By the time she first undertook cognitive behavioural therapy (CBT) four months ago to try to stop her compulsive habit, it had become such a part of her life that she burst into tears: “I said: ‘I don’t know if I can stop, because it’s been a part of me for 20 years.’”

Davidson has tried numerous potential solutions over the years, including expensive facials, hypnotherapy and wearing gloves; she says CBT – one of the most common psychotherapy treatments for the disorder – has been the most effective. But Penzel says treatment for compulsive skin picking can be complex, depending on the severity of the case and the likely cause.

Dr Anjali Mahto, a consultant dermatologist at the Cadogan Clinic in London, says she often sees cases of acne excoriée (a skin-picking disorder in which patients squeeze acne spots or even healthy post-acne skin). “When people come to the clinic, what you don’t see are the spots – you just see the areas of skin that people have gouged out because they’ve tried to get rid of the spots.”

Although Connor and Davidson report feeling anxiety, stress and frustration in relation to their skin picking, Penzel says it is a common misunderstanding that it is all down to stress. “People do these things when they’re either overstimulated, meaning stressed or even happily excited, or they do it when they’re understimulated, meaning when they’re sedentary or bored. So it provides stimulation when you’re understimulated and it reduces it when you’re overstimulated – it works either way.” Anxiety and depression don’t cause it either, he says. “They might aggravate or exacerbate the problem, but they’re not what causes it. That’s important to understand.”

Figures suggest that 75% of people affected by skin-picking disorder are female, but Penzel is wary of the picture this paints – women are more likely to seek treatment than men and there have been few comprehensive studies.

Jacqueline Kilikita, 26, recalls an incident last year when she picked at the flaking skin on her lips so severely that she ripped off a large piece of skin, causing her bottom lip to bleed heavily. “I also pick the skin on my cuticles and sometimes my scalp, so I researched my symptoms and every single one of them was consistent with dermatillomania.”

In her role as beauty editor at the website Refinery29 UK, Kilikita published an account of her experience. “After I wrote the article, a colleague mentioned that she suffers, too. The comments also showed me that lots of people are in the same boat. One said it was a relief to know that they aren’t alone.”

Reflexology has been helpful for her, she says, but it is expensive; keeping lip balm and moisturiser on hand is a cheaper way to reduce the compulsion: “If the skin is moisturised or covered in product, I’m less likely to pick.” Trying CBT is next on her list.

Penzel advocates a comprehensive BFRB-specific approach to behavioural therapy that falls under the umbrella of CBT. “We try to look at the entire clinical picture, everything surrounding the problem that feeds into it, because if you don’t do it comprehensively you’re not really going to get it under control,” he says.

Another key issue is a lack of understanding of the disorder and how to treat it within the psychological and medical communities. “A lot of people get some very bad reactions from health professionals – unfortunately, a lot of it is passed off as bad habits, but it really isn’t,” says Penzel. “This can rise to a great level of seriousness and it should be taken very seriously.” At extreme levels, he has worked with people who have needed plastic surgery or have contracted secondary infections such as flesh-eating disease (necrotising fasciitis) as a result of severe skin picking.

Connor and Davidson say stigma can be a barrier to getting treatment. Of the “handful” of men to whom Connor has spoken who also experience skin-picking disorder, only a few have told their family, friends and doctors, he says. “They just don’t feel people will understand their situation, which I completely get.” In fact, he made the decision to share his account of living with skin-picking disorder on Instagram in the hope of creating a support network.

Davidson says that, for years, she had no idea that she was suffering from a psychological disorder: “It was just something I did.” She thinks this lack of awareness is very common. “A lot of people don’t realise that you can get help – a lot of people do really think they’re strange, that they’ve got this weird thing that nobody else has.”

If you are affected by any of the issues raised in this article, contact Anxiety UK’s national Infoline service on 03444 775 774 or the US-based TLC Foundation for Body-Focused Repetitive Behaviors at bfrb.org