Thank you for your support of alternative nontoxic hair color. Allergies aren't to be taken lightly. Some allergies may develop over time with repeated exposure. Allergies can even build over a week after coloring. Just because EcoColors is p phenylenediamine (ppd) free, doesn't mean you won't react. There are other oxidative dyes present in nontoxic amounts that some individuals may be allergic to. Make sure to have a medical plan in place with your physician in case you experience any kind of allergic symptom.