CONCORD, N.C. -- Daytona 500 winner Trevor Bayne may never learn what caused the illness that has sidelined him the past five weeks.
An insect bite initially caused Bayne to seek treatment after he experienced numbness in his arm during an April race at Texas. He thought everything was fine after, then woke up with double vision two days after the April 17 race at Talladega.
Roush Fenway Racing sent him to the Mayo Clinic, where he spent a week undergoing tests to determine what was causing his symptoms.
"I think I finally just had to accept that nobody knows," Bayne said Thursday at Charlotte Motor Speedway. "I still don't have an official diagnosis, but they treated everything they thought it could be and since then everything has gone away. To me, they hit something."
Bayne said he went through a series of MRIs, a spinal tap, and at one point had 16 needles in him at the same time. All of it could rule out what he didn't have, but nobody could pin down what he did have.
In the end, doctors simply said he suffered from an inflammatory condition.
"It is not anything terminal or anything like that," Bayne said. "I heard somebody say cancer and leukemia and those things, but that is not even a word that I heard in the hospital. That was not even an option. They have ruled out all those things."
Bayne believes he could have simply been worn down from the whirlwind month he experienced after becoming the youngest winner in Daytona 500 history. The 20-year-old was the surprise winner of this year's season-opening race, and the media attention on the fresh-faced Bayne had him flying all over the country for appearances.
"It could be just a series of events where you get a bug bite and your immune system is down and we had been running for a couple months hard every day after Daytona and it wears down your immune system," Bayne said. "That is what I am hoping for. Whether that is it or not, only time will tell with that."
Bayne said his symptoms have cleared up and he could have raced this weekend at Charlotte. But RFR officials wanted to hold him out one more week, and he'll now return for next weekend's Nationwide Series at Chicagoland Speedway.
His next Sprint Cup race will be next month at Michigan for the Wood Brothers.
"That was a no-brainer with Trevor and Ricky being best friends," team owner Eddie Wood said. "Trevor is going to help him with the transition because he went through the same thing at Texas last fall of having to make the show and Ricky will have to make the show as well."
Bayne is eager to get back in his car, but was genuinely thrilled to just be back at the track.
He made a point to single out drivers who had shown him support the last five weeks, including Michael McDowell, who visited Bayne for five days, Carl Edwards, who brought his guitar on a visit to the Mayo Clinic, and Tony Stewart, who gave Bayne's family use of his plane to travel from their home in Tennessee to Minnesota.
RFR president Steve Newmark touched upon the difficulties the organization faced concerning the 20-year-old Bayne's privacy rights during his hospitalization.
"We recognize that when the youngest winner of the Daytona 500 misses a number of races with a mysterious illness that it is newsworthy," Newmark said. "We also recognize this garage is a small community and there were rumors running rampant about all sorts of sinister things that were going on.
"Hopefully all the focus (will now) be on how well Trevor is running on the track."
Bayne has tested twice so far, at Rockingham Speedway and the road course at Virginia International Raceway. He said he was tired after Rockingham, but that the VIR session went well and made him eager to get back to racing.
"I'm 100 percent confident that when I get back in the car, it's going to be just like before," he said.