Itching of the scalp after using hair dye is usually due to an allergic reaction. Hair dye manufacturers recommend using the dye on a “test patch” of skin two to three days before coloring your hair to rule out sensitivities.
A common irritant in hair dye is paraphenylenediamine (PPD). PPD allergy symptoms may include itching, scaling, redness and swelling of the scalp, face and ears. Individuals who previously dyed their hair with no adverse reaction may develop an allergy with subsequent hair color treatments.
While most reactions to hair dye are mild, report any symptoms of allergic reaction to your doctor. Rarely, sensitivity to PPD or other hair dye ingredients may cause acute allergic reactions such as marked swelling, hives, difficulty breathing, dizziness, chest pains and other potentially dangerous symptoms. Seek immediate medical attention for any severe or persistent reactions.
Individuals sensitive to permanent hair color may benefit from semi-permanent dyes or rinses. Alternatively, natural dyes such as henna or other plant-based colorants may be considered. As with any hair dye, perform a “test patch” before coloring the hair.