Textiles

Dye class according to application

Main substrates

Dye classes according to chemical structure

Described as allergens

Acid

Nylon, wool, silk (also paper, inks, leather)

Azo, anthraquinone, triphenylmethane, azine, xanthenes, nitro, nitroso

Rare

Azoic

Cotton, rayon, cellulose acetate, PET

Azo

Rare

Basic

Polyacrylonitrile, modified nylon, PET (also paper, inks)

Cyanine, hemicyanine, diazahemicyanine, diphenylmethane, triarylmethane, azo, azine, xanthene, acridine, oxazine, anthraquinone

Rare (Basic Red 46 – important allergen in acrylic socks)

Direct

Cotton, rayon, nylon (also paper, leather)

Azo, phthalocyanine, stilbene, oxazine

Rare (some cases of immediate type allergic reaction)

Disperse

PET, polyamide, acetate, acrylic (also plastics)

Azo, anthraquinone, styryl, nitro, benzodifuranone

Most frequently

Mordant

Wool (also leather)

Azo and anthraquinone

Very rare

Reactive

Cotton, wool, silk, nylon

Azo, anthraquinone, phthalocyanine, formazan, oxazine, basic

Described only as occupational allergens

Solvent

Plastics, fuels, varnishes, lacquers, inks, oils, waxes

Azo, triphenylmethane, anthraquinone, phthalocyanine

Rare

Sulfur

Cotton, rayon

Indeterminate structures

Exceptionally rare/none

Vat

Cotton, rayon, wool

Anthraquinone, indigoids

Exceptionally rare

While there are thousands of C.I. generic names, each manufacturer can invent a trade name for given colorants, and, consequently, there are more than 50,000 names of commercial colorants [1, 5, 6]. All this brings confusion in the identification of the dyes used by the consumer.

15.4 Main Allergens Among Textile Dyes

The main textile dye allergens belong to disperse dyes (DDs) – azo or anthraquinone types. At least 26 DDs are described as contact allergens in the scientific literature [2].

The prevalence of DD contact allergy varies depending on the population and the dyes tested. In those studies in which patients appeared for routine patch testing and DDs were included, prevalence values range from 0.4 to 6.7 %.

Available data indicates that the prevalence of positive test reactions at least to three dyes (D Blue 106, 124, and D Orange 3) is over 1 % when screening dermatitis patients [2].

Some dyes are forbidden by the EU Commission as carcinogens and some are listed as “allergenic,” but it is obvious that there are many more allergenic DDs.

15.5 How and What to Test?

Patch testing with commercial textile dye preparations.

European baseline series are not suitable for the reliable detection of textile dye allergy. p-Phenylenediamine (PPD) once was considered a marker for allergy to disperse azo dyes, but recent studies point out frequent concomitant positive reactions to PPD and disperse azo dyes, which are not always due to cross-reactivity. It is discussed whether a textile dye mix made from several DDs should be included in the European baseline series. Testing with specialized series, created by commercial patch tests suppliers (e.g., Textile Colours & Finish by Chemotechnique, Sweden), can be very helpful. Of note, patch testing with some dyes can result in strong or very strong (++/+++) reactions. Some positive reactions may be persistent and itching up to 3 weeks.

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