If you’ve ever dyed your hair you know that the box will usually suggest to do an allergy test at least 48 hours before you plan on dying your hair. This 19 year old woman in France named Estelle did not do the allergy test like she was supposed to. Estelle opened the box 30 minutes before she planned on dying her hair, and tried the allergy test. Nothing apparently happened so she went ahead and dyed her hair with the solution. A couple days later Estelle felt her scalp itching, and then her forehead started to swell. Antihistamines didn’t work, so she went to the hospital and got some stronger medication. Unfortunately when she got home her tongue began to swell and caused her to have difficulty breathing. It turns out she was allergic to a chemical called PPD that’s illegal in most makeup, but is a common chemical used in hair dye.