When Nikki Cook discovered her daughter chewing on the living room rug, she thought Charlotte was just being inquisitive. Most babies explore new things by putting them in their mouths and the mum-of-two had no idea her little girl was any different.
However, this was just the first sign that Charlotte was suffering from pica, a rare condition which is characterised by an appetite for inedible items. Now aged five, like many of her friends she loves unicorns and horses, and her favourite film is the Disney classic Dumbo. But she also can't get enough of fibrous materials and has so far chewed her way through soft toys, several carpets and even a £2,700 sofa.
"She is literally eating us out of house and home," Nikki, 42, from Lanark, says. "Although Charlotte's been diagnosed with pica, there's very little me and my husband Alasdair can do to stop her from eating what she wants. I've tried explaining to her how dangerous it is and even physically stopping her. But it's like an addiction, she just can't stop."
The first sign of Charlotte's unusual cravings came when Nikki noticed that the pile on her living room rug was becoming thinner. The lime green mat was new and initially she just assumed it was faulty. That was until she started to find the same colour strands of material in her daughter's nappies.
"I realised she was eating it then but I wasn't really worried," Nikki remembers. "My older daughter Evelynne had always bitten Velcro when she was a baby but she'd quickly grown out of it. Even my health visitor said it was just a phase."
Nikki and Alasdair, 35, removed the rug from the living room and assumed they'd solved the problem. However, this was far from the case. When Charlotte moved from a cot to a bed and could get out of it on her own, Nikki noticed there was similar material in her nappy again.
Searching her daughter's bedroom, she found a bald patch on the carpet underneath Charlotte's bed. And not long afterwards, she moved on to munching on her soft toys and her sister's carpet, too.
"I had no idea what to do," Nikki says. "She was chewing right through to the stuffing inside the toys and eating that too. The doctor didn't seem to be taking me seriously and, however much I told Charlotte not to do it any more, it didn't make any difference. She'd look like she didn't understand or just smile and keep on doing it.
"I tried putting pepper and chilli powder on the carpet, telling her it would make her ill, and even physically stopping her from eating things, but nothing worked."
Eventually, in October 2012, Nikki managed to get Charlotte an appointment with a paediatric doctor, who immediately diagnosed her with pica. Although sufferers can crave everything from ice cubes to soil to chalk, in Charlotte's case it was a taste for fibrous materials.
"As soon as we walked in, Charlotte climbed under the doctor's chair and started chewing on that and the carpet. I'd never heard of pica before but it was a relief to get a diagnosis. At last I thought something could be done."
Charlotte was also diagnosed with autism but, despite doctors knowing what was making her eat material, there was nothing they could do to curb her unusual cravings. And no matter how hard her parents tried to remove as many things
as possible from Charlotte's reach, even things like her car seat fell prey to her teeth.
"We looked online but there isn't much information out there," Nikki says. "The doctors had very little advice as how to deal with it, and it's a real worry. I'm terrified she's going to choke, or if there's a big ball of fluff building up inside her.
"It's also really difficult to try and get her to eat regular food. She doesn't mind Shreddies, yogurt or chicken nuggets with chips, but she only eats these as and when she wants. The doctor said she is the correct weight and height for her age but I'm terrified having this condition is affecting her health."
Despite their family and friends being supportive, Nikki and Alasdair realise it is a difficult condition to understand unless you are living with it. And not only are they worried about the impact pica might be having on Charlotte's future, the financial implications are also a strain.
"We can't keep replacing everything she eats. When she first ate the carpets, we replaced them with ones with a shorter pile, but that hasn't stopped her. Now we have wooden floors downstairs but we can't afford to remove the carpets upstairs too. It's the same with the sofa and cushions she's eaten."
All the couple can do is keep a close eye on Charlotte and vet her toys to check they won't pose a danger to her if she starts to eat them. "We don't know what the answer is. There is no magic wand," Nikki says. "We just have to ensure that she is never out of our sight."
Nikki and Alasdair have only found one other family whose teenager is affected by pica and, after struggling to find a charity to help them, they're hoping to set up a support group for others in their situation.
"We have no idea what the future holds for Charlotte," Nikki says. "She's five now and nothing has improved since she was diagnosed. But we're determined to spread awareness of pica – to help Charlotte and other sufferers like her."
By Harriet Rose-Gale