Maria Mahnken has lost all her hair, but she wants people to know that she's not sick. Credit: NBCChicago.com

Maria Mahnken is not sick. It says so on the business cards the 6-year-old hands out.

The reason people might think otherwise is that Maria is almost entirely bald -- which people often associate with cancer and other critical health issues. What Maria really has is alopecia universalis, a condition that causes hair loss but doesn't pose any major health risks.

"Alopecia means your hair falls out, and your body's allergic to your hair," she told her classmates at Montessori Children's School while being filmed for NBC News.

Maria, who lives in the Chicago suburb of Elmhurst, told NBC News she has a wig but doesn't like to wear it. She would rather other people change their minds before she changes her appearance.

"Thank you for your concern," reads the cards she hands out. "I am not sick. I have alopecia universalis. Only my hair is sick. To learn more about alopecia, please visit www.naaf.org. Thanks! Maria."

The cards have been a big help, Maria told NBC News, especially with other children. "I just like that they don't call me baldie anymore," she said.

Her mother, Elene, likes the way the cards are working, too.

"We're hoping that by telling Maria's story, we'll get not only the awareness to help her, but all the other millions of people out there who do have this illness," the mom told NBC News.