Campbell Pruden was only 19 months old, just beginning to talk, when she developed a limp and begged to be carried. The only way she could express her pain was to tell her parents, "It's too tight."
In 2011, the once energetic toddler was diagnosed and hospitalized with systemic juvenile idiopathic arthritis. At one point, she was taking eight daily medications. She was so afraid of the frequent steroid injections that she had to be put under anesthesia to keep her still enough for the procedure.
"In the beginning when there were all those unknowns, we knew we had to get to the bottom of it," said her mother, Kim Pruden, a 35-year-old speech pathologist from Phoenix.
"But at the same time, we had to keep that poker face with her to give her the confidence that, 'You are O.K. and you are going to be O.K.'"
The couple has their "breakdown" moments after Campbell goes to bed at night.
One of the greatest misunderstandings about arthritis is that it affects only adults. More than 300,000 children in the United States are living with the disease, according to the Arthritis Foundation, which has launched a new public awareness campaign to debunk the myths of arthritis during the month of May.
In addition to swelling in the joints, children can suffer muscle and soft tissue tightening and bone erosion that affect growth patterns.
Symptoms may include a non-contagious fever and rash. Inflammation can affect the spleen or the membranes that covering the lungs and heart.
It's important to recognize the symptoms of arthritis early, as many forms of arthritis can cause irreversible joint damage, often within the first two years of the disease. There are more than 100 types of arthritis and knowing what type you have makes a difference in how it is treated.
Today, at age 3, Campbell gets intravenous injections of powerful immune-suppressant medicines known as biologics, but office visits can last anywhere from two to five hours long. She calls the tiresome procedures her "stupid tubes."
Pruden laughs that the ordeal is like "going to Disney World for kids to get poked with needles."
Pruden and her husband John take a positive approach with their daughter whose joints are always aching.
"We keep her moving, we keep her active and we take one day at a time," she said. "When she is not feeling well, we respect that, but it's important not to make that a crutch or an excuse."
Arthritis is an umbrella term used to describe the many autoimmune and inflammatory conditions.
One family hard-hit by the disease recently moved from rainy Seattle to Charleston, S.C., for the warm climate, which is easier on the aching joints of sufferers.
Sisters Amelia, 5, and Liberty, 3, have juvenile idiopathic arthritis, which affects their joints "from head to toe," according to their mother, Lisa Schultz, who was recently diagnosed with rheumatoid arthritis.
Their father has had gout since he was 20, which is also a form of arthritis.
Amelia was diagnosed in April 2010 when she was nearly 2. She suddenly stopped walking and reverted to crawling.
"She started limping in the morning and wanted to be carried," said Schultz, 37 and a stay-at-home mother. "She would cry when I changed her diaper, too. I would lift her up and she would say her toes hurt when I put on her socks. Her second toe was almost the size of her big toe and her knees were the size of oranges."
Amelia's younger sister was just 15 months old last November when she, too, developed juvenile arthritis. Like her sister, she had painful joints; both stopped growing. Just recently, Liberty has developed inflammation in her right eye related to her arthritis and takes drops six to eight times a day. Untreated the condition, uveitis, can cause blindness.
"One day in the tub I saw that one knee was way bigger than the other knee, but I thought there is no way possible I would have two kids with it," said Schultz. So far Liberty is "in better shape" than Amelia. The family has a son, 7, who shows no signs of arthritis.
Both girls had tried anti-inflammatory and steroid medications, often the first line of defense for treating arthritis.
In the last decade, there have been significant advances in the treatment of arthritis, especially for those who do not respond to conventional drugs. The most important has been the development of a group of drugs called biologic response modifiers or biologics.
Now, like Campbell Pruden, the girls these biologics, known as TNF (tumor necrosis factor) inhibitors that suppress the inflammatory response seen in arthritis.
So far, neither of the Schultz girls has any joint deterioration. But their mother worries about potential side effects with these powerful biological medicines -- one of them lymphoma.
"It's scary," she said. "But we don't have a choice. Years ago kids were in wheelchairs and crippled. Now, with the medicines, you wouldn't be able to tell they have arthritis."
As for Campbell Pruden, she is now in a "holding pattern," doing well as doctors have cut back on her medications. Her parents keep her off red meat and dairy, part of an anti-inflammation diet.
"She can have some sort of remission, but it will be in her body for the rest of her life," said Pruden. "You never know when there is going to be a flair up. Right now, we just hope it stays dormant.
Nowadays, Campbell joins her parents hiking and on other outdoor activities. "She's a trooper and wants to do everything we do," said her mother.
Just recently Campbell got a fever and her parents worried she was taking a downward turn. "Doctors ruled out a flair-up [of her arthritis] -- it was an early version of the flu," said Pruden. "If it's flu, I'll take it."
The Prudens' greatest reward comes from helping others with the disease.
"I make it my mission to raise awareness," she said. "These children live in pain every day and can't even wake up and go to school because of the pain in their body. We need to find a cure, to find a way for these kids to lead strong, happy lives."