Hair dyes can cause allergic reactions, including itchy, red skin, swelling or more rarely, anaphylaxis, which is a life-threatening condition requiring immediate medical attention. Contact your doctor if you suspect an allergy to hair dye, and avoid permanent coloring products in the future.
Cause
The most likely cause of itchy red skin associated with hair dye is the chemical paraphenylenediamine, also known as PPD, according to the New Zealand Dermatological Society. It is widely used in permanent hair dyes to set color, but is also found in photocopying inks, dark cosmetics, photographic developer and temporary tattoos. Reactions commonly occur on the tips of the ears, scalp or eyebrows, although irritation may spread to the rest of the face as well.
Testing
Your doctor can administer a patch test in her office to determine if you have an allergy to PPD, or you can conduct a test at home. Rub a small amount of the hair coloring on your wrist or the inside of your elbow. Leave the solution on for 48 to 72 hours. If no irritation occurs, your rash probably is not caused by hair dye. Wash the solution off immediately, though, if you experience redness or irritation, in which case you can safely assume you are allergic to hair dye.
Treatment
Wash your hair and skin thoroughly with a gentle shampoo or soap if you experience irritation or itching. Apply a 2-percent hydrogen peroxide solution to the area. Apply a moisturizing lotion or a hydrocortizone cream to relieve intense itching while your skin heals. Contact your doctor immediately if you experience swelling, wheezing or difficulty breathing.
Considerations
Avoid permanent hair dyes in the future, and try semi-permanent products instead. Do a patch test first, though, because approximately 10 percent of people who are allergic to permanent hair dyes can't tolerate semi-permanent products either. Some people who are allergic to PPD may also experience sensitivity to azo dyes found in ball-point pens, PABA found in sunscreen, sulfa drugs and benzocaine, a local anesthetic used by dentists, according to the New Zealand Dermatological Society.
