I always dread it when the news media cover cosmetic claims. It’s almost always alarmist language designed to stoke up fear and outrage backed up by the most spurious of data. So when I saw a headline online saying that ‘Hypoallergenic products on sale at Boots and Superdrug fail the allergy test’ I feared the worst.
And it was pretty bad, but not quite as bad as these things generally are. The headline suggested that there was a test for products that would cause allergies. No such test exists. But in fact it was misrepresenting a reasonable sounding study that had simply looked at ingredient lists of products marketed as hypoallergenic and discovered that many of them contain known allergens.
That wasn’t something I found remotely surprising. Anything can provoke an allergic reaction. It simply isn’t possible to formulate a product that nobody can potential have a reaction to. As such it isn’t possible to ever justify the claim hypoallergenic. The best you can do is minimise the risk. Mesoallergenic maybe? But even that is not very straight forward.
The problem is that what we call an allergen isn’t something that is easy to define. In the study being reported on they had used the British Society for Cutaneous Allergy (BSCA) baseline series. That sounds like an authoritative list of allergens, and indeed it is. It’s a sort of hit parade of materials that have generated a lot of reactions in dermatologists’ patch tests. But unfortunately it’s not really a simple list. The practice of patch testing just isn’t straight forward enough to lend itself to scoring different materials for their potential to cause allergies.
The difficulties dermatologists face are formidable. Take a simple material like aluminium, which was the American Academy of Dermatologists’ allergen of the year last year (they’ve awarded this honour to a different one every year for twenty years now). This exists in a great many forms which will vary enormously in how readily they get through the skin let alone how likely they are to provoke a reaction when they get through. Every material behaves differently depending on how you treat it, how you apply it and what medium you apply it in. And the people to which it is being applied are pretty variable too. We can react differently to the same thing at different times and with different bits of skin. And different individuals are very different.
All in all it is amazing that they manage to get any usable data at all. But given the constraints that they face they do a pretty good job. It’s an impressive indication of the benefits of many years of study and experimentation.
But even so, it really isn’t possible to categorise materials as allergens with any degree of precision. And it certainly isn’t possible to designate any material as non-allergenic. It isn’t really possible to even pick out materials that have a low risk of allergic reactions. And even it were, what use would it be? Would it be meaningful to say that this product as a 0.01% risk of triggering an allergy, but this one has a 0.001% risk. What can you do with that information?
Basically the hypoallergenic claim is meaningless. Ideally the industry should drop it. In the meantime I suggest you ignore it.
I’ve blogged about this subject before:
I’ve even talked about how to formulate hypoallergenic products.