For years, Allison Ross rubbed in skin-lightening creams with names like Hyprogel and Fair & White. She said she wanted to even out and brighten the tone of her face, neck and hands. Mrs. Ross, 45, who lives in Brooklyn, also said that she used the lightening creams “to be more accepted in society.”

After months of twice-a-day applications, her skin was not only fairer, it had become so thin that a touch would bruise her face. Her capillaries became visible, and she developed stubborn acne. A doctor told her that all three were side effects of prescription-strength steroids in some of the creams, which she had bought over the counter in beauty supply stores.

“I never read the labels,” Mrs. Ross said. Instead, she took her cues from friends, many of them, like her, from the West Indies. “Once somebody told me Fair & White was the one they were using, I’d go to the Korean store and ask for it,” she said.

Dermatologists nationwide are seeing women of Hispanic and African descent, among others, with severe side effects like Mrs. Ross’s from the misuse of skin-lightening creams, many with prescription-strength ingredients, which are sold in beauty shops and bodegas and online.