Shortly after being diagnosed with tonsillitis, a British woman died from an immune disorder that left her unable to eat.

Chelsea Jackson, 20, of Wolverhampton, England, had been fit and healthy but developed a sore throat on December 22, Metro reported. She was soon unable to swallow, her eyes turned yellow and she was having difficulty breathing.

Jackson was diagnosed with hemophagocytic lymphohistiocytosis (HLH). According to the National Institutes of Health (NIH), the condition causes the body makes too many activated immune cells. These white blood cells attack other blood cells and collect in the spleen and liver, causing the organs to enlarge, according to Johns Hopkins Medicine. It typically develops during the first months or years of life and has a high mortality rate— a median survival of less than two months to six months after diagnosis.

Jackson underwent chemotherapy but the treatment did not extend her life.

“We had no idea how serious things were about to get,” her mother, Nicki, told Metro. “Tonsillitis is a common illness and everyone normally recovers but her body wasn’t responding to the medication.”

Her family has set up a GoFundMe page to create a registered charity in their daughter’s name and raise awareness.