Hair Dye Allergies – Introduction
About 5% of permanent hair dyes users develop allergy, mostly in the form of an allergic contact dermatitis with redness and itching in the head area, but systemic reaction with involvement of the whole body skin and other organs is possible in severe cases. Hand dermatitis affects considerable percent of hair-dressers . The main cause is substance PPD.
PPD (4-ParaPhenyleneDiamine, C6H8N2)
PPD is widely present on the market since 1909, and it is still used in over 2/3 of permanent hair dyes. Commercial hair dye product typically comes in two bottles: the one with PPD based dye (non-oxidized and thus colorless) and the other with oxidizer or developer, usually hydrogen peroxide (H2O2). In the hair dying process initially the peroxide is used to break down the natural hair pigment melanin, and then the PPD is used to replace melanin. When PPD reacts with peroxide it becomes partly oxidized and colored — it is this form which may cause allergy. Fully oxidized PPD does not cause allergy, so PPD sensitive persons can wear fur coats dyed with PPD safely . PPD can be also found in some dark colored cosmetics and temporary tattoos. In France, Germany and Sweden, PPD was banned as a hair dye because it was thought to be too dangerous for health .
Alternative names for PPD: PPDA, Orsin, Rodol, Ursol.
PPD and PPD Related Substances
Other hair dye substances thatcan cause allergy: 6-hydroxyindole, Isatin, p-Methylaminophenol
Substances related to PPD that may also cause an allergic reaction:
Local anesthetics benzocaine and procaine
Sulfa drugs
Para-aminobenzoic acid (PABA) in sun-protective creams
Para-aminosalicylic acid used for treatment of tuberculosis.
Hair dyes producers misleadingly use certain terms. “Hypoallergenic” hair dyes should less likely cause allergies, but this is not proven. “Fragrances free or unscented” only means the product has no odor, but this does not reduce their potential allergenic action. A hair dye that is completely “natural“ can still trigger an allergic reaction in a sensitive person.
Types of Allergies Caused by Hair Dyes
Allergic contact dermatitis (ACD) is an immunologic skin reaction occurring in a genetically predisposed individual; the risk of becoming sensitive rises with coloring frequency . At least 10 days after initial use of PPD is required for an individual to develop a specific sensitivity. On the second and subsequent exposures to PPD, an allergy reaction can develop in 6-72 hours (delayed hypersensitivity). In this process, PPD molecule are attacked and destroyed by certain immune cells (macrophages and lymphocytes), resulting in creating of skin granuloma, redness or vesicles. Affected areas – eyelids, ears, skin at hair line, beard or neck - are usually well demarcated but may propagate beyond the site of contact with a hair dye. Symptoms are itching or burning feeling.
Contact urticariacan develop in minutes to about 1 hour after exposure. PPD triggers production of IgE antibodies and release of histamine causing dilation of skin vessels and leaking of blood plasma into the skin resulting in skin redness and edema (swelling of the eyelids) . Contact Urticaria Syndrome (CUS) with red patches over the entire body, and bronchial asthma with wheezing, sneezing, difficult swallowing and vomiting can appear.
Anaphylactic shockis extremely rare but life threatening condition. Facial swelling, grasping for air, blood pressure fall, and death, if not immediate help is available, is a usual sequence of events. It was reported that a 38 year mother died in UK in August 2000 shortly after changing her hair dye. She was asthmatic before, and she firstly developed anallergy with scalp itching after using her old hair dye for some months. After changing the dye, anaphylactic shock developed, and she died within an hour after applying it.
Allergy Sensitivity Test
Hair dye consumer can apply a solution (i.e. dye and developer mixed together) behind the ear or on the inner side of the elbow for 48-72 hours. If no irritation or rash occurs during this time, the test is negative and the hair color may be considered as safe to use. If a rash of a certain size (according to test scale) develops, this is a sign of allergy.
Dermatologist will use a patch test. A patch with a 2% PPD in petrolatum is applied to the upper back and checked after 48 hours. Negative reactions show no skin changes; positive reaction can vary from a mild rash to prominent blisters or ulcers. In “ready-to-use” T.R.U.E. patch test, 24 possibly allergy causing substances (including PPD) are tested at once.
Treatment of PPD Allergy
In acute severe hair dye dermatitis caused by PPD, the hair and scalp has to be washed thoroughly with a mild shampoo. 2% hydrogen peroxide solution or compresses with potassium permanganate in a 1:5000 dilution have to be applied to completely oxidize the PPD. To soften the crust, a wet dressing of olive oil and lime may be used.
The patch test has to be made afterwards to determine if there an allergy to PPD exists, or there is only a non-allergic contact dermatitis present. In the case of proven allergic dermatitis, corticosteroid cream, which reduces allergic immune response, can be applied.
