Amoxicillin, a commonly prescribed antibiotic, can cause skin rashes in 5–10 per cent of children. These range from mild non allergic rashes to serious allergic reactions like hives or anaphylaxis.

The first time two of Taylor Lucero’s children were prescribed amoxicillin, they developed bad rashes. “It was horrible,” she said. Luciano Lucero, 8, and his older brother Gabriel, 11, are two of an ...