Tragic Kayleigh Box, 28, was diagnosed with the debilitating disease at just 11 months old after she became poorly and failed to gain weight.
She suffered years of pills, intravenous antibiotics, physiotherapy, nebulisers, hospital stays and appointments to battle the condition.
Her immune system was left extremely fragile and meant she was susceptible to germs.
In December, the trainee vet contracted bronchopneumonia from someone coughing near her while she went Christmas shopping in her hometown of Malvern, Worcs.
Her family claim she tried to get an appointment at a cystic fibrosis clinic but it took a week to get a slot.
Despite being rushed into intensive care, Kayleigh, died on January 17.
Devastated mum Dawn Box, 53, said Kayleigh died because someone failed to cover their mouth when they coughed.
She said: “She had a bit of an obsession with germs and bugs. She hated being near people with colds and coughs, because she usually caught something as her immune system was low compared to a healthy person.
“So many times she ended up in hospital after catching a virus from somewhere.
“She used to say ‘Can’t they put their hands over their mouths when they cough?’.
“She obviously caught the pneumonia from someone who maybe coughed when she was stood next to them, and had her life taken away from her by something that’s a million times worse than a common cold.”
Dawn told how Kayleigh wasn’t feeling well during the festive period but was unable to get an appointment for a week.
She added: “I am so angry that it took so long to get an appointment. She was given two weeks of intravenous antibiotics.
“On Christmas Day, she finished the IVs but said she felt terrible.
“She tried to smile as much as she could that day and she did her best to be okay. She rarely complained.”
The Tuesday after Christmas, Dawn took Kayleigh to Heartlands Hospital in Birmingham but was told there were no free beds.
They returned on January 2 and as there were no free beds on the cystic fibrosis ward, Kayleigh was taken to another ward.
Dawn said: “Her lung function had dropped ten per cent to 36 per cent. She was coughing up blood, felt sick and couldn’t breathe.
“She was put on a non-invasive ventilator mask for two weeks which helped her to breathe.
“She was reduced to using a commode. She was diagnosed with bronchopneumonia, and the doctors said we would have to look at the possibility of a lung transplant when she was better.
“Her doctors were liaising with the intensive care unit for two weeks, who told us that she wasn’t ill enough to be admitted to intensive care.”
She added: “She was so scared of going to sleep in case she didn’t wake up.”
Dawn received a call on January 16 telling her to come in because they were transferring Kayleigh to intensive care.
Although Kayleigh seemed to have improved at first, she soon started getting worse.
Dawn said: “She was put on a ventilator at 11pm and was given fluids. The doctors were doing everything they could for her.
“But two hours later she was in an induced coma. She looked so peaceful.
“We left at about 2am on January 17, but we were called a few hours later by the hospital.
“We went to the hospital straight away and the doctors told us there was nothing more we could do for her.
“I was hysterical. They told us that if they put any more air into her lungs, they would explode.
“It was truly unbearable.
“The last thing she said to me was ‘I’m so sorry I’ve put you through this. I love you’.
“She was terrified that cystic fibrosis would kill her, but it was pneumonia that took her away from us.
“Something so simple and unavoidable as a cough has taken my perfect daughter away.”
Kayleigh leaves behind two brothers, Kristopher, 30, and Daniel, 25, and boyfriend Adam Whitehouse, 41.
Dawn, a self-employed cleaner, added: “The past few weeks have been a living nightmare for all of us. We just can’t believe it.
“She was the perfect daughter and sister. Kayleigh has left a huge emptiness in our hearts.
“She was beautiful inside and out. She was such a wonderful woman who fought until the end.
“She was fun, bubbly, outgoing, and had a wonderful sparkle in her eyes. I’m going to miss her terribly.”
Since Kayleigh’s death, her family have raised £1,000 for the Cystic Fibrosis Trust.
Cystic fibrosis is caused by a genetic mutation. It is a condition where the lungs and digestive system get clogged with thick sticky mucus.
The symptoms usually begin in early childhood and include persistent coughing, poor weight gain and recurring chest and lung infections.
There is no cure for the condition, but treatment to ease symptoms includes antibiotics, physiotherapy and bronchodilators, which make it easier to breathe.
In some cases, a lung transplant may be required. It is estimated that more than 9,000 people are living with cystic fibrosis in the UK.