Another common form of autoimmune alopecia is alopecia areata. When people talk about alopecia, they are often referring to this type, which affects one in every 500 to 1,000 people in the United States. It’s unclear what kind of alopecia Pinkett Smith has, but her appearance suggests it is alopecia areata, said Dr. George Cotsarelis, a dermatologist at the Perelman School of Medicine at the University of Pennsylvania. Alopecia areata can arise in childhood, adolescence or adulthood, Dr. Lamb said. People who have the condition tend to lose hair in clumps, she said, causing round bald spots. (The word “areata” refers to the patchy nature of the hair loss; when a person loses all their scalp hair, it’s called alopecia totalis, and when they lose all their body hair, it is referred to as alopecia universalis.)
