Three-year-old Caitlin Soleil Lucas is often full of questions but one has left her parents - and even doctors - struggling for an answer.
They have been trying to find out how some insect bites, which she found on her right ankle last September, have gone on to cause a host of life-threatening symptoms.
The Filipino family flew from Manila to Singapore last Monday, in the hope that experts here will be able to diagnose her condition.
Outside the paediatric intensive care unit at the National University Hospital (NUH), where Caitlin is now warded, her 30-year-old mother, Ms Christine Del Feliz Lucas, recalled how the bites quickly developed into skin lesions that spread to her legs, arms and face.
On New Year's Day, Caitlin was first hospitalised in Manila after suffering severe abdominal pain.
We'd always explain to her what the doctors or nurses would be doing... She knows we're honest with her. And once she understands, she will be brave about it.
MS CHRISTINE DEL FELIZ LUCAS, Caitlin's mother, seen here with husband Jericho Jose Lucas at NUH
"Her lesions were fading, but she started to have low platelet and red blood cell counts, swollen lymph nodes, night sweats, blasts in her blood, and diarrhoea," said Ms Feliz, who runs a fashion business.
Caitlin also had an enlarged spleen and liver, which pushed against the surrounding organs, at times causing her heart rate to spike. Her family members found themselves shuttling between different hospitals in Manila.
"The doctors were all puzzled because, while she would show symptoms for the different illnesses, the test results would come back inconclusive," said her wedding photographer father Jericho Jose Lucas, 34.
The couple arranged to take Caitlin to Singapore, after doctors told them it could be leukocyte adhesion deficiency - a rare autoimmune disease, for which tests are not available there.
Over the past two months, Caitlin has gone through many procedures in a bid to get a clear diagnosis - from bone marrow aspirations, blood extractions and lymph node biopsies to more than 20 blood and platelet transfusions.
Despite the pain and discomfort, she has remained calm, only once losing her cool.
"We'd always explain to her what the doctors or nurses would be doing, sometimes using her toys," said her mother. "She knows we're honest with her. And once she understands, she will be brave about it."
The lowest point for Caitlin's parents was around a month ago, when their bubbly daughter stopped smiling and talking to them.
"It was like she almost gave up fighting and it broke our hearts," said Mr Lucas, who added that Caitlin had weighed just 10kg by then.
Gradually, they raised her spirits through small words of affirmation, and by reading her favourite story - David And Goliath.
After being admitted to NUH, Caitlin's condition has improved slightly, as doctors continue working to uncover her diagnosis.
With medical costs rising, her parents have exhausted their savings and spent more than 3.5 million pesos (S$104,000), largely through fund-raising efforts led by friends and strangers. After starting their Facebook page "Courageous Caitie", many have turned up with gifts and prayers for the family, even during their stay in Singapore.
"Caitlin told us that when she is better, she wants to see the mountains in Baguio and go to the beach," said Mr Lucas. "She wants to live up to her name, as Soleil means 'sun'."