Is it really an allergy to washing powder?
Although laundry detergents are widely regarded as one of the most important causes of allergic contact dermatitis (ACD), studies show that the prevalence of powder allergy is quite low (<1%) [1,2]. According to scientific analyses, allergens contained in powders are generally nullified to clinically insignificant levels during machine washing [1,3,4].
Such allergens include:
- fragrances,
- preservatives
- dyes,
- surfactants,
- emulsifiers
- bleaches.
Already in the 1990s, in an American study, more than 10% of the 738 patients undergoing patch tests believed that washing powder caused their allergy symptoms. However, only just over 2% of doctors were willing to confirm this diagnosis [1,5]. This says a lot about the discrepancy between common knowledge and the scientific basis of knowledge. It also demonstrates that making a diagnosis on one’s own, based on one’s own observations, can lead astray.
In the case of symptoms indicating a powder allergy, other causes should also be considered. These include, for example, hypersensitivity to the material of the garment and textile allergens such as dyes and textile resins. It is also worth considering initiating a diagnosis for atopic dermatitis [1].
What can be allergenic in washing powder?
This does not mean, of course, that the problem of allergy to washing powder does not exist, but only proves that there is a misjudgement of the danger. Credible evidence for the allergenicity of detergents found in powders can be found aplenty.
- Methylisothiazolinone
Methylisothiazolinone (MCI/MI) is the best known of these allergens. It has attracted the interest of scientists because at one time it caused an epidemic of allergic contact dermatitis [1,6]. It has been ongoing since the beginning of the 21st century and peaked in 2013-2014, while it has already been ended by the European Union’s regulations on the composition of personal care products [1,6].
The concentration of chemicals in a given washing powder is of key importance in terms of its allergenic properties. It determines to a large extent whether an adverse reaction occurs. Although it is also influenced by a number of other factors [1].
Methylisothiazolinone in concentrations of 100 ppm (0.01%) or less should not cause sensitisation [7]. At the same time, it is worth remembering that this preservative is not only found in washing powders. It can also be found in:
- some baby wet wipes,
- disposable nappies,
- various types of cosmetics (creams, body lotions, washing gels, bath lotions, soaps, shampoos, conditioners, mascaras) [8].
- Other allergens
Laundry powders, even those marketed as safe for sensitive skin – despite being institutionally controlled – can still contain a number of irritants, such as surfactants (decyl glucoside and lauryl glucoside) and propylene glycol [1]. In particularly sensitive individuals, these substances trigger not only allergic reactions, but also – and perhaps above all – irritant contact dermatitis.
People with AD are particularly at risk and are more likely to develop sensitisation [1]. To avoid skin problems, it is therefore worth paying attention to compositions.
Allergy-friendly washing powder – what kind?
Allergy-friendly washing powders should not contain added fragrances or other allergenic chemicals (unless in low enough concentrations). Some certified laundry detergents, besides having a low allergenic potential, are additionally able to eliminate 95% or more of the allergens found on clothes [9]. A list of powders, washing liquids and fabric softener concentrates recommended by the Polish Society of Allergology available on the Polish market can be found on the PTA website under ‘Products for the allergic’. However, it should be remembered that even a hypoallergenic formula does not reduce the risk of allergy symptoms to zero.
