Most textiles will have some sort of textile dye to impart a color to the garment and yes, this may trigger some skin issues that it's worth knowing about. Although this is not considered “common”, as a physician you learn that the only way a diagnosis can be made is if someone suspects it. If you don't think about it or know about it then you can’t diagnose it.
What kinds of textile dyes are there?
Even if you think your white t cotton t-shirt isn’t dyed, it actually might be because the natural hue of cotton is not that stark white color you are accustomed to seeing.
Basically, anything that attaches to or reacts with the fabric and leaves a hue behind can dye your clothing. Different types of dyes are needed for different types of fabrics since natural fibers and synthetics may attach to dyes differently.
There are lots of different dyes out there but certain ones are more linked to skin rashes and interaction with the skin than others.
Which textile dyes are more likely to cause allergic contact dermatitis?
Out of the dye classes, the one most commonly associated with contact dermatitis is the disperse dyes. There are case reports of contact dermatitis or cases of hyperpigmentation of the skin with VAT dyes, azoic dyes, acid dyes, and direct dyes.
It is important to bear in mind that the standard patch testing offered by many dermatology practices includes two disperse dyes, paraphenylenediamine and disperse blue 106, but not necessarily the other types of dye classes. This makes textile dye patch testing challenging as these particular dyes are only used on polyester clothing. For dyes used on cotton, we do not have readily available patch test panels available to use for testing in routine outpatient clinics.
The range for reported incidence of contact dermatitis to textile dyes is wide - the data is not consistent. Since not every practice offers testing, it is even more challenging considering the rates are likely underreported. I have seen numbers for frequency of contact dermatitis to textile dyes range from under 1% to over 30% with most numbers in the 3 to 5% range. The other challenge is simply that if a textile dye reaction is not suspected, it may not be tested. Education on the existence of these reactions is essential.
Table | Textile dye classes, fabrics, benefits/risks, and associated health concerns.
How is textile dye contact dermatitis diagnosed?
We are often left to determine through a little detective work based on clinical history, patterns of rash, and common co-reactants on patch testing to figure out if a textile dye is a possible trigger. Also, ruling out other causes such as reactions to laundry detergents can help narrow choices.
For example, one study from Sweden showed that the most common pattern of distribution of rashes from textile dyes tends to be rashes on arms, face, neck, and underarms. This study also showed that women with a higher frequency of hand rashes. Think about why this may have been. For textile dyes to trigger reactions, usually the fabric is wet and the dye is dislodged to come into contact with the skin to trigger a reaction. The areas where moisture would tend to build up would likely be the areas we tend to sweat more- around the neck, under the arms, and face if there is a point of contact with textile there. A large review of textile contact dermatitis to textile dyes included socks, undergarments, and pantyhose as sources found in case reports. This also implies sweat and friction as possible triggers.
Patch testing with traditional allergen panels may actually still be helpful since one study found that a positive reaction to a disperse dye called paraphenylenediamine, or ppd for short, was seen simultaneously with other disperse dye reactions in over half the cases.
Another challenge to throw into this process is that some reactions may not be to the dyes themselves but to intermediates in the process of dying which I came across in one case report for a VAT dye allergy.
With all the challenges of diagnosing textile dye dermatitis, what should I do if I think I might be allergic? Should I just buy only cotton clothing? Only white or black clothing?
As with all information we have, the question is what we do with it. Remember that allergies to textile dyes are not considered common but clearly possible. I wish it was as simple as saying that if you choose just one type of fabric such as cotton or polyester you could avoid it but this just isn't the case. Although disperse dyes are the most common class of dyes associated with contact dermatitis and are used in polyesters and not cotton, there are other dye classes such as azoic dyes, acid dyes, and direct dyes that are used in cotton that have also had reactions.
I wish it was as simple as saying to just choose white or black clothing but unfortunately, many white textiles are dyed to be white as the natural color or cotton for example is not stark white. Black textiles may have paraphenylenediamine, a disperse dye, used to make them black.
Also remember your contact with textile dyes is not limited to clothing, it is also found in upholstery for furniture, bed sheets, towels, and other sources.
So what can you do? It is essential to work with your dermatologist to determine an accurate diagnosis for your rash- verify if it is truly a contact dermatitis. Once this is verified, think about the time of onset, location of your rash, the potential role of clothing, upholstery, bedsheets, and towels in terms of point of contact, moisture or sweat, and friction. Patch testing for common allergens can help but may not provide a full picture. Remember that if it is possibly linked to a particular clothing item or brand, trying a different brand is reasonable. Since there is a full range of colors that have tested positive for different individuals, it is not as simple as trying particular colors or fiber types. Also consider the role of layers, especially if it is a type of apparel that is required to be worn. For example, if it is a work shirt or sports uniform, layering a clothing item underneath can reduce the direct contact between your skin and the garment. More research is needed to really understand how effective laundering clothing can be in removing the reactive components of dyes.