PALO ALTO -- Every day, 8-year-old Doris Diaz puts on a coat of pink lipstick. As the day wears on, pink deepens to crimson as she coats and recoats, dabbing her lips with ever-deeper shades of red. Doris has started every morning this way since she was 3 years old -- for her, lipstick is about much more than keeping up appearances.

When she was 6 months old, Doris was diagnosed with cystic fibrosis. For most of her life, she's been in and out of the hospital; as time passed, the occasional overnighter became consistent, weeklong stays. This time, Diaz has been in the hospital since June, sleeping with her Hello Kitty cosmetic kit by her side. To keep her spirits up, she has a zoo of stuffed animals on her bed and her room is draped in pink, but lipstick comforts her most.

"I brush my teeth, brush my hair, then put my lipstick on," she said. "It makes me feel pretty."

Cystic fibrosis is a chronic respiratory disorder that causes difficulty breathing, coughing as well as frequent lung infections. Four times a day, for up to an hour, Doris is strapped to "the vest," a rattling treatment that physically shakes her rib cage, clearing her lungs of excess mucus.

Dr. Carlos Milla, director of the cystic fibrosis program at Lucile Packard Children's Hospital, considers Diaz's case one of the most serious he's ever seen. "It's uncommon to see someone her age be this sick," he said.

According to Milla, without a lung transplant, Doris' life expectancy could be as short as a year. Doris is now waiting for a donor.

Doris has lived with cystic fibrosis for as long as she can remember. As her condition worsens, she finds herself more and more restricted: no more trips to Los Angeles to visit cousins, no more sand castles at the beach. Mom and dad are forced to make constant trips between Lucile Packard Children's Hospital and Newark, where the family of five lives.

"A regular day would be to go home after work, spend the day with my family," said David Diaz, Doris' father. "With Doris, that has all changed."

Doris doesn't like school much, in part because it becomes too apparent how cystic fibrosis limits her. "I don't get to do things that other kids can do, like run, or play tag, or do all of those things," she said. "I'm not like them."

A self-described "drama queen," Doris is the quintessential preteen girl. Dressed in pink from head to toe, she occasionally punctuates her whiplike sarcasm with a well-practiced eye roll. Once, she ribbed a hospital associate for failing to wear lipstick.

"When Doris saw [her], she said 'what's going on with you? Why aren't you wearing lipstick?'" said Corina Romero, Doris' mother. "She can't live without her lipstick."

Romero has made her own little home next to Doris' bed. At night, Doris gets lonely and insists on someone staying the night with her. On a regular weekday, Romero will commute across the bay four times to be with Doris, pick up her two other kids and hand them off to her husband before staying the night.

"If I don't find somebody to stay with her, she calls me constantly because she doesn't like to be here by herself," Romero said. "During the week, when everyone is at work, it's very difficult."

As children grow, cystic fibrosis makes it harder and harder for them to breathe. When she was much younger, Doris would be admitted to the hospital once, maybe twice a year; now, she's a regular patient. With increasing frequency, regular days are being interrupted by the vest's rattling treatment. School is broken up by ever-lengthening hospital stays.

The Diaz family stays strong by leaning on family and faith. Relatives from both sides visit Doris, and sometimes an uncle will stay the night to give Doris' parents some rare alone time.

"It's been difficult," Romero said. "We find a way. My husband helps, my family helps, God helps. Somehow we make it work."

More and more, a "normal" day for Doris begins in her hospital bed and not at home or at school. On the days she can go to school, she carries an oxygen tank. She's made a close group of friends but still doesn't like it much. "It's so boring," she said. "You have nothing to do instead of learning."

But Doris still looks forward to her "favorite subject" -- recess. Every day, she and her friends walk to a familiar spot under the swings; sometimes, friends even help her with the oxygen tank. Together, they empty their cosmetic kits and put on lipstick.

Contact Edward Ngai at 408-920-5064.