On the 22nd September 2020, ECHA’s committees backed the restriction of over 1000 skin sensitising chemicals used in clothing and other articles.
With up to 5 million European citizens having become sensitised to chemicals present in textiles, leather and synthetics, the move will be welcomed by those who experience skin rashes from dark blue dye, nickel in jeans buttons and reactions to unknown chemicals in faux fur.
Once a person becomes sensitised to an allergen, like Nickel, they must “avoid exposure to it for the rest of their life to prevent allergic reactions” according to ECHA.
The definition and distinction between sensitisation, intolerance and allergy are not entirely clear. What you think each word means is likely to be an opinion formed from your own experiences. Immunologists, medical professionals, and regulatory scientists are unlikely to agree wholly with each definition.
Intolerance
Intolerance is probably the most agreed upon definition. If you are intolerant, you lack the biological capacity to deal with and eliminate the substance in question. This is not usually life threatening. The symptoms are generally gastrointestinal unhappiness. An example of intolerance would be lactose intolerance.
Sensitivity
ECHA appear to take the position that sensitivity is the beginning of the path to a full-blown allergy and of course this may be true. It’s also true to say that sensitisation can occur and only ever result in mild symptoms such as the rhinitis experienced with hay-fever. Sensitivity doesn’t usually result in a life-threatening condition though sensitivities or “allergies” to animal fur and other triggers can be extremely uncomfortable and sometimes activity limiting. The symptoms of reaction in a sensitisation case generally occur in the organ and specific location of exposure: The rash will appear where the button touched the skin, or where the shirt was worn.
Allergy
A severe allergic reaction can trigger anaphylaxis and is potentially life-threatening. The immune response is swift and exaggerated and is usually triggered by food proteins, insect stings and medications. Symptoms occur immediately. Often the first reaction is not severe but the second and subsequent responses can be exponentially severe. Symptoms of reaction occur systemically; for example, the first reaction from a bee or wasp sting may present as a large area of skin irritation or inflammation around the sting site and hives may appear in non-connected areas of the skin. The throat and respiratory tract may be affected, and the heart rhythm may become abnormal.
Regulatory sensitisation data
Thankfully ECHA do accept alternatives to animal testing for the skin sensitisation endpoint though animal studies are still conducted in some instances. Any laboratory test can only indicate a potential for sensitisation and the data is only as good as the test design. So much is still not clearly understood about the immune response during a sensitisation skin contact and how and why this can escalate to or be different from a severe allergic response that it’s sometimes difficult to be sure based on test data alone.
All done with chemicals?
It’s not always synthetic chemistry which causes skin allergic reactions. Natural sensitisers, which may be exempt from REACH registration, can also cause an allergic skin reaction. If your product use is professional or consumer use, regardless of what regulations you need to follow, now is a good time to assess skin sensitisation potential to pre-empt any restrictions which may be coming your way.
