"There are days when we take her bandages off and I look at what's underneath the skin and it's red raw, and I just think: 'I don't know how she can be as happy as she is,' and I want to cry"

When your daughter is born with an incurable skin disorder that means the slightest knock or rub can cause painful open wounds, how do you, as parents, cope? Emma Cowing talks to an ordinary couple facing an extraordinary challenge and meets the little girl who lights up their lives

• Rachael and Andy Grist make sure playtime is still fun for their baby daughter, Isla, but tending to her wounds is painful for the child and parents.

ISLA GRIST IS sitting on a daybed, fresh out of the bath. At 19 months old, with beautiful eyes and a shock of strawberry blonde hair, she is happily engrossed in a picture book about animals. But this is far from an ordinary bathtime. Around her, three women are quietly embarking on the twice-weekly process of keeping Isla's skin together. "Shh, sweetheart," says her mother, Rachael, as she gently inserts a needle into an angry red arm blister and her daughter looks up in pain. "Everything's going to be OK."

Isla has Recessive Dystropic Epidermolysis Bullosa (EB), a devastating genetic skin disorder for which there is no cure. Her body is missing Collagen VII, a vital protein that holds the skin together. Without it, her skin is exceptionally fragile. The slightest knock or rub can cause painful open wounds and blisters all over her body. Her feet, which have been missing layers of skin since birth, are constantly red raw. Her fingers are prone to fusing together, and have to be kept separate with special tape. Her arms, legs, back and front are covered in large red sores. The blistering is not limited to her skin either. The inner linings of her body, such as her mouth and her oesophagus, also blister, making eating incredibly difficult. Often, the blisters on her skin do not have time to heal before a fresh one appears in the same place, and infections are common. She may be less than two years old, but Isla has already experienced more pain than most of us will feel in a lifetime.

Today she is having her bandages changed, something that happens in the Grist household – a home on the Black Isle overlooking the Beauly Firth – twice a week. It is a slow, painstaking process, and one that Rachael, 34, and her husband, Andy, a 36-year-old Squadron Leader at RAF Kinloss, are unable to take on alone. Instead, a children's community nurse from nearby Raigmore Hospital in Inverness is here to help, as is Pippa Millican, a specialist EB nurse who works with the charity DebRA, which is dedicated to supporting families affected by EB.

"Half the battle is keeping her occupied," says Millican as Rachael embarks on a round of Row, Row, Row Your Boat, and Millican takes the opportunity to gently wrap the special bandages that help keep Isla's skin from becoming more damaged round her arms. "It's not a very exciting place for her to be, and, of course, it's painful, so we do what we can to keep her entertained."

Isla is given pain medication, including Oramorph, a type of oral morphine, before the process, but it is clear that she still finds parts of the procedure, such as the lancing of blisters, which is done with a small, fine needle, painful.

"It's difficult for her because she can't tell us where it hurts," says Rachael. "We're just guessing. I don't want her to get addicted to the pain relief but it's really difficult to find a balance."

The Grists met at a summer ball at RAF Lossiemouth in 1998, when Rachael – who is from Inverness and worked as a data analyst for companies such as Tesco – came along as a date of one of Andy's friends. They married in 2002 and their first daughter, Emily, was born in 2006. However, tragedy struck when a second child, a little boy named Fraser, developed a kidney infection in the womb. He was born at 20 weeks and died shortly afterwards. The couple were devastated, but chose to try again. When Isla was born in July 2008 at home in Lancashire, where Andy was based at the time, after Rachael unexpectedly went into labour, it was apparent very quickly that something wasn't right.

"The paramedic crew ran in the door just as she popped out," says Andy. "We could see immediately that the skin on her feet was all blistered and she had something wrong with her hands."

In fact, the top five layers of skin on her feet had been pulled away during the birth – and the paramedics radioed ahead to the hospital to say that the damaged skin looked like a burn, although it obviously wasn't. Isla was taken into the local special care baby unit, and the next few days were incredibly difficult for the young family.

"We got very wide-ranging advice from 'that's completely normal' to 'brace yourself, your baby could die very quickly'," says Andy.

In fact, it was two weeks before Isla was diagnosed with Recessive Dystrophic EB. At first, the Grists didn't know what had hit them.

"For the first six weeks of her life we carried her around on a padded mattress barely touching her, because we just didn't know what our touch was going to do to her skin," says Rachael. "It was only gradually that we learnt what would and wouldn't damage her. A lot of it was trial and error."

EB is rare enough that many people who see Isla's condition have no idea what is wrong with her. The disorder affects one in 17,000, and there are currently around 5,000 sufferers in the UK. There are a number of different forms of EB, with the milder ones causing blistering mainly on the hands and feet, and the most severe causing death in early infancy. Isla's is one of the more serious forms of EB. As well as all the problems with her skin, feeding is a serious issue, as eating is so painful for her due to internal blisters, and she suffers from constant itching. She also has problems sleeping – often sleeping for just three hours a night, then waking every 40 minutes thereafter. In other ways, however, she is a perfectly normal little girl.

"I've started taking Isla to playgroup as it's the only time she gets to play with other children," says Rachael. "It's chaos – there are lots of children jumping and banging into each other and it's quite a stressful experience, but it's one I've got to let Isla experience. I've got to let her do it. These are the kids she's going to go to school with and she's got to play with them. I can't hold her back from that. But I am next to her all the time."

Children, say the couple, are far more understanding of Isla's condition than adults. "Children just accept it. But if Isla's fallen on her face and lost big chunks of skin and you go out to the shops, you are very conscious that people are staring," says Rachael. "They're not being nasty, they're just staring."

"There will come a point where she starts to understand she's different," says Andy. "Right now I don't think she understands that she's any different from anyone else."

The Grists' home is a happy place. Their elder daughter, Emily, plays happily with her little sister, whom she plainly adores, and the family works hard to keep even the most difficult parts of Isla's care and treatment positive experiences. But for both Andy and Rachael, one of the hardest things has been seeing their daughter go through such pain.

"There are days when we take her bandages off and I look at what's underneath the skin and it's red raw, and I just think, 'I don't know how she can be as happy as she is,' and I want to cry," says Rachael. "I think sometimes I could cry every day if I wasn't as positive as I am."

"I just cry," admits Andy. "Sometimes when I see her without her bandages – and because I'm at work I only see her every few weeks without them whereas Rachael sees them twice a week – I can get quite a shock and think, 'That really is a lot worse than it was.'"

"Sometimes you have to block it out and say, 'Once the bandages are back on it'll be fine,'" says Rachael. "It's not, but for me, that's my way of coping." The other way that both cope is by fundraising for the charity DebRA. As well as providing the Grists with monthly visits from a specialised EB nurse, DebRA has also given the family special silk sheets for Isla's bed, soft clothing (Isla wears most of her clothing inside-out, so the seams don't irritate her skin), sheepskin rugs and other specialised products it can be difficult to source, as well as a lot of understanding, advice and support.

"It's nice to know you can just ring people who've been through it," says Andy. In April, Rachael will run the London marathon for the charity and, in June, Andy and three RAF colleagues will cycle 1,600 miles round Scotland. It is a remarkable way to say thank you.

At this stage, the Grists don't know what Isla's future holds. Life expectancy for children with Isla's form of EB varies, and Andy says he sometimes torments himself by going online and reading the obituaries of other children who have suffered from the condition, trying to work out how far the disorder has developed. "I think it will get a lot more difficult," says Rachael. "At the moment she's in a buggy and I can take her for walks with the dog, but in three or four years I don't know if she'll be able to walk as far as we walk with the dog. She might not even be able to walk to the car. We just don't know. I don't like to look too far ahead. I deal with today and enjoy today, and plan for what we're going to do tomorrow. Because I think our time with her is going to be limited, we don't know how long that's going to be, so I think we're going to have a really good time and we're going to try what we can. You could spend a lot of time thinking about what the future will be like and not enjoying the present, and for me it's the present that's really important."

The Grists' greatest wish for their daughter is simple. "It's happiness," says Andy. "Yes," says Rachael, gently picking up her giggling daughter, who is blissfully unaware that both of her parents are close to tears. "Her life is fun despite all the unpleasant things and the pain," says Rachael. "She's happy. She enjoys what we do with her and we all have happy memories. It's not all about hospital visits and sore skin and infections. It's the fun times."

Isla, sitting on her mother's knee, smiles widely, claps her hands and nods in wholehearted agreement.