Hair colourants – allergies and cancer?

You probably know someone who is allergic to something. Or perhaps you are.

Just as allergic reactions can occur in certain individuals to a whole range of things, including foods, pollen and insect bites, certain hair colourant ingredients can cause allergic reactions in susceptible individuals.

Severe allergic reactions to hair colourants are rare. (Skin irritation is different from allergy, but also undesirable! See more at Some health-related terms – defined.)

One known allergen and skin irritant is paraphenylenediamine (PPD). This ingredient or its derivatives are used in many permanent hair colourants. However, hair colourants containing PPD are safe for most people when used according to the manufacturer’s instructions. Only an estimated 0.2% of people develop a PPD allergy as a result of hair colourant use, according to a 2008 German study.¹ 

To minimise any chance of allergy and irritation, and to prevent hair damage, hair colourant products may carry warnings and have important instructions for use. Mixing and applying the product, wearing gloves, leaving the product on for the correct amount of time, etc.

Doing a skin patch test 48-hours before use is very important. This test needs to be performed each time, as you could develop sensitivity with repeated use. You might not have a full-blown allergic reaction, but skin irritation is also possible.

In Australia, all hair colourants must include a full list of product ingredients. If you have a reaction, patch-testing by a dermatologist could help identify the ingredient responsible, so you can avoid it in the future.

There have been several studies investigating a possible link between use of hair colourants and various cancers.

Studies into the possible link between hair colourant use and bladder cancer have been inconsistent, with some studies showing no increased risk and others showing increased risk. A slightly increased risk of non-Hodgkin’s lymphoma has been found for women who used hair dye before 1980, but no increased risk was found for post-1980 hair dye users. No links between hair colourant use and breast cancers has been found.²

Significantly, the International Agency for Research on Cancer (IARC), considers personal hair dye use to be ‘not classifiable as to its carcinogenicity to humans’. However, IARC has concluded that long-term exposure from working as a hairdresser or barber is ‘probably carcinogenic to humans’. Some studies have found an increased risk of bladder cancer in these professions.

In Australia, hair colorants are classified as cosmetics. Cosmetic products in Australia are some of the safest in the world. All ingredients must on the Australian Inventory of Industrial Chemicals or be officially approved by the regulator, AICIS. AICIS assesses all industrial chemicals on a priority basis, e.g. in response to new concerns about their health or environmental safety.

You might have seen warning labels on some hair colourant products, like CAUTION or POISON. That means one or more ingredients in the product are also ‘scheduled’ via the Poisons Standard. This national classification system controls how more hazardous chemicals are made available to the public as well mandatory safety warnings on labels.

Additionally, the Australian Competition and Consumer Commission (ACCC) has strong powers to remove unsafe products from sale.