What are the signs that you are allergic to hair dye?

Itching and redness: New hair dyes should be tried first on a small area of scalp b4 applying to all head.

Itchy scalp rash.: Allergy to chemicals found in hair coloring would typically be first noticed as an itchy red rash on the scalp or hairline. It is a condition called contact dermatitis. Blistering may occur. The face, neck, and eyelids may also be involved. Some people might get red swelling, such as hives in these areas as well. Diagnosis would involve a chemical patch test by an allergist or dermatologist.