EXPLAINER: Alopecia affects millions, including kids

Millions of people around the world are affected by alopecia areata, an autoimmune disorder that causes hair loss and was thrown into the spotlight after actor Will Smith slapped comedian Chris Rock at the Oscars.

The slap stunned millions, drew widespread condemnation and earned Smith a 10-year ban from the ceremony after he apologized. It came after Rock threw a pointed joke that some felt was insensitive at Jada Pinkett Smith about her hair loss.

Advocates said at the time that increased awareness about the condition, which is fairly common but little discussed, could be a small bit of good to come out of the blowup. Wednesday, Jada Pinkett Smith, dedicated an episode of “Red Table Talk” to the disorder.

Here’s a look at the disorder, and how hair is tied up with beauty and race, culture and self-identity:

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WHAT CAUSES ALOPECIA?

Alopecia areata can make hair fall out of the scalp in patches and also affect other parts of the body, like eyebrows and nose hair.

Alopecia can come on quickly, is unpredictable and can be incredibly tough to deal with mentally, said Brett King, a hair loss expert at Yale Medicine, told The Associated Press in March.

“Imagine if you woke up today missing half of an eyebrow,” he said. “That unpredictability is one of the things that’s so mentally treacherous and awful because you have no control of it ... it’s a disease that strips people of their identity.”

While seldom discussed, it’s actually fairly common: the second biggest cause of hair loss, after male or female pattern balding. About 2% of people have it. It’s not physically painful, in some cases it spontaneously goes away and it can be treated.

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HOW DOES IT AFFECT WOMEN? WHAT ABOUT KIDS?

While it’s unclear if Rock was aware...