A 25-year-old woman died just over a month after catching the flu, when her symptoms triggered a rare and life-threatening condition. Rachel Catterall's daughter, Daisy, first phoned her complaining of swollen glands in her neck, but within weeks she had developed hemophagocytic lymphohistiocytosis (HLH), in which an overactive immune system attacks the body's organs and blood cells.
Rachel, a painter and decorator from Cirencester, had never heard of HLH before her daughter's death and is now speaking out to raise awareness of the disease. She described watching doctors work on Daisy and being told she could not be saved. "I could see they were right. Her body had been ravaged by this hideous disease. Basically, her own body was killing her," she said.
A Sudden Decline
Daisy, who worked for the local council, had recently bought her first home with her long-term boyfriend, Matty, now 27. She was an avid gym-goer and, according to her 55-year-old mother, had never been ill in her entire life. The couple had been travelling the world and making plans to marry and start a family.
In January 2025, Daisy called her mother about swollen glands. Doctors told her it was a viral infection and prescribed antibiotics. Over the following weeks, she continued to visit doctors as achy joints and rashes developed. "They all said it was the same thing and that she had nothing to worry about," Rachel recalled.
Hospital Admission and Diagnosis
The week before Rachel and her husband, Sam, also 55, were due to travel to Cambodia and Vietnam, Daisy was admitted to hospital after blood tests showed an abnormal count. She was discharged the day before her parents left and was due to be treated as an outpatient.
Two days into the trip, the couple received a call that Daisy was back in hospital. During a FaceTime call, a consultant said he wanted to perform a bone marrow biopsy. "I began looking for the first flight home," Rachel said. After landing back in the UK, Daisy had been transferred to critical care, and doctors gave the HLH diagnosis.
Final Days and Legacy
Despite her condition, Daisy remained concerned about making a planned trip to the Philippines. She was placed in an induced coma to help her body recover, but went into cardiac arrest and died on 22 February 2025 at nine in the morning.
Rachel and her family have since created a group called "Daisie's People" to raise funds for the team at University College London Hospital who oversaw Daisy's care. So far, they have raised £86,000. More than 500 people attended Daisy's funeral, and her ashes are being scattered across the globe, including in Australia, Iceland, Spain, Thailand, Cyprus, Gozo and the Philippines.
Rachel urged doctors to "think outside the box" and test for HLH when patients present certain symptoms, noting that many could have died from the condition while being diagnosed with something else. "She squeezed more adventures and fun into 25 years than most people do in a lifetime," she added. "I hope she will continue to inspire everybody to do the same – as you never know how long you've got."
