Contact allergies are common. The main culprits are fragrance chemicals, preservatives and hair dyes. In hair dyes the most common allergen is paraphenylenediamine or PPD. PPD is an ingredient with high temperature stability, strength and chemical resistance. For this reason, it is used in textiles, fur-dyeing, dark-coloured cosmetics, rubber chemicals, engineering polymers and composites, plastics, photocopying and printing, black rubber, oils, greases, gasoline, pigments and hair dyes.
PPD increases both the intensity and longevity of a dye. For this reason, it is now added to some temporary tattoos – for example, it is added to real henna to make “Black Henna” which is advertized as both temporary and harmless. Henna has been used for centuries in the Far East. Derived from a shrub, it is a natural product and has been used for skin tattooing and in hair dyes where it provides a reddish hue to the hair. Henna tattoos last for a couple of weeks. PPD intensifies the colour, increases definition and speed up the tattooing process. The addition of PPD also allows the tattoo to last longer. Moreover, Brancaccio and others found that the concentration of PPD in temporary tattoos can be as high as 15.7% which is greater than that used in hair dyes.
Redlick and DeKoven reported on 6 women who, over a 2-year period attended their dematology clinic. All the women had a strong allergic reaction to PPD and also to other para-dyes that cross-react with PPD. These include paratoluenediamine, aminophenol and 2-nitro-4-phenylenediamine. The patients suffered from edema, pruritis and erythema on scalp, hairline, eyelids or cheeks or some combination thereof, about 1 to 2 days after they dyed their hair. Most importantly, all had had at least one black henna tattoo.
As study by Sosted and colleagues of 2,9039 patients in 12 dermatology clinics found a positive reaction to PPD in 3.5% of patients. The most frequently reported cause of allergy in 55.4% was hair dye with 8.5% of the cases as a result of the use of temporary henna tattoos.
Tattoos are increasing popular in body art. Estimates range from 40% to 75% of North American women and girls who dye their hair and the number of men and boys who dye theirs is increasing. This is not restricted to North America. It is an increasing problem world-wide. Women who have had temporary tattoos can become sensitized with subsequent exposure resulting in a delayed Type IV hypersensitivity resulting in acute contact dermatitis. Thought direct application of PPD to the skin is prohibited by the US Food and Drug Administration, temporary tattoos are unregulated.
As a contact allergen it can result in an allergic reaction, allergic dermatitis, eczema and even scarring of the skin. Severe reactions can result in urticaria and, rarely, anaphylaxis. Contact dermatitis due to PPD in hair dye can affect not only the scalp but the face, neck, eyelids and forehead. It can result in permanent skin changes.
Hair dyes are potent skin sensitizers. Sensitization can result in reactions to other products including black clothing, hair dye, fur and leather dyes and printer and facsimile ink. It can also causes an allergic reaction to related substances such as
- semi-permanent and temporary hair dyes (both synthetic and organic)
- rubber products such as latex gloves and support stockings
- inks used in ballpoint pens
- gasoline and diesel oil
- colouring agents used in foods and medications
- sunscreens that are not PABA-free
- azo dyes, sulfa drugs and the local anaesthetics benzocaine, tetracaine and procaine that are used by doctors and dentists. It may also cross-react with thaizide diuretics.
A study of hair dye products available in the USA found potent contact sensitizers in almost all of them. PPD was found to be the most common allergen before resorcinol and m-aminophenol. The researchers found that the dyes contained 30 potent sensitizers.
- Brancaccio RR, Brown LH, Chang YT, et al. Identification and quantification of para-phenylenediamine in a temporary black henna tattoo. Am J Contact Dermat 2002;13:15–8.
- Matulich J, Sullivan J. A temporary henna tattoo causing hair and clothing dye allergy. Contact Dermatitis 2005;53:33–6.
- Redlick F and DeKoven J. Allergic contact dermatitis to parapheylendiamine in hair dye after sensitization from black henna tattoos: a report of 6 cases. CMAJ 2007; 176(4): 445–446
- Sosted H, Rustemeyer T et al. Contact allergy to common ingredients in hair dyes. Contact Dermat 2013; 69(1): 32–9 doi: 10.1111/cod.12077.
- Hamann D, Yazar K et al. P-phenylenediamine and other allergens in hair dye products in the United States: a consumer exposure study. Contact Dermat 2014; 70(4): 213–8 doi: 10.1111/cod.12164