Kelly Osbourne feared people would think Lyme disease diagnosis was drug relapse

Kelly Osbourne kept her Lyme disease diagnosis secret because she feared people would wrongly assume she was back on drugs.

Ozzy and Sharon Osbourne's daughter contracted the condition after she was bitten by a tick during a party for the rocker's 56th birthday back in 2004, when her mother had a reindeer sanctuary installed at their Los Angeles home.

The 32-year-old wasn't properly diagnosed for a decade, and after finding out she was suffering from the disease she chose to keep quiet because she thought critics would think she was hiding behind the medical issue.

"They thought that, 'Oh, she's just doing drugs again, oh, she's relapsed or she's doing this or that'," Kelly told The Dr. Oz Show, "and nobody believed me. So I was a bit nervous.

"Until I was informed enough about it and then seeing so many people suffer from it and knowing... meeting other people that also had it, you really start to realize how huge of a problem this is. And there's not enough information out there about it for people."

Osbourne was initially misdiagnosed with epilepsy after suffering a seizure while filming an episode of E!'s Fashion Police show in 2013.

"Through all the testing that they did in the hospital, they found that I had scarring on my brain, so they assumed that I had been having more seizures and not knowing," she added.

Kelly spent the next year being treated for the disorder, which caused a lot of problems: "They put me on brain tranquillisers, a (anti-epilepsy) medication called keppra, and I would only have about two hours of lifetime a day," she said. "I had my driver's license taken away. I was, like, 'This is awful', and then I had a side effect, so they gave me medication for that side effect, and that gave me a side effect, so they gave me a medication for that side effect. I had this bag of pills that was so big and one day I was just, like, 'I can't do this anymore'."