Prognosis

How a Shampoo Preservative Triggered a Rash Epidemic

 Constant scratching.

Photographer: Kinga Krzeminska/Moment RF/Getty Images

Hi, it’s Bob in New York. The rash that appeared on my arm in June was astonishingly itchy, and no one could figure out what caused it. But first …

My doctor at first thought the eczema-like rash that appeared on my left arm was due to poison ivy.