Hair Dye Safety: Allergy Tests and Reactions

Why hair dye can cause reactions

Many permanent and some semi-permanent hair dyes contain PPD (paraphenylenediamine), a chemical known to irritate skin and cause allergic reactions. You may be more at risk if you've ever had a black henna tattoo, because the paste can contain high levels of PPD, which can sensitise you to it.

Reactions are fairly common but usually mild. Severe allergic reactions are rare.

Before you dye: the 48-hour test

1. Read the instructions on the pack. Each brand describes its own test.
2. Test at least 48 hours before you plan to dye. The NHS recommends testing on a strand of hair, and you can also buy home patch-test kits.
3. Check for a reaction over the next 2 to 3 days. Symptoms can take up to 72 hours to appear.
4. Don't use the dye if you react or feel unwell after the test.

Repeat the test every time, even with a product you've used before.

Safer dyeing at home

Do:

• wear the gloves supplied
• follow the timing exactly: never leave dye on longer than recommended
• keep dye away from your eyes
• rinse thoroughly with mild shampoo straight away if you feel a reaction starting

Don't:

• dye your eyebrows or eyelashes with hair dye. The FDA warns this can hurt your eyes and may even cause blindness
• use PPD dyes if you've ever reacted to hair dye or a black henna tattoo
• use dye on a scalp that is cut, sore or irritated

Signs of a reaction

• stinging or burning
• an itchy rash on the scalp, ears, neck or face
• dryness, tightness or soreness
• blisters

On white skin a rash may look red. On brown or black skin it may look darker brown, purple or grey, or be harder to see.

What to do if you react

1. Rinse your hair and scalp thoroughly with mild shampoo and water.
2. For mild symptoms, a pharmacist can suggest an emollient or antihistamine cream or tablets.
3. See a doctor if symptoms are getting worse. They may prescribe steroid cream or tablets and may refer you to a dermatologist for allergy patch testing.
4. Don't use that dye again, and tell your hairdresser.

Emergency: swelling of the lips, mouth, tongue or throat, difficulty breathing or swallowing, blue or grey skin or lips, sudden confusion or fainting. Call your local emergency number.

Removing dye stains from skin

Hair dye on your hairline and ears usually fades within a few days with normal washing. Use gentle methods and avoid scrubbing irritated skin. Applying a barrier of petroleum jelly along your hairline before dyeing helps prevent staining. Our videos below show practical tips.