Reading labels with a fragrance allergy

Fragrance is the most common cause of cosmetic contact allergy and the least informative word on a label. One entry can stand for dozens of individual substances, and the US rules permit exactly that.

Why one word covers so much

Cosmetic labelling requires ingredients to be declared by their established names, and it makes an exception for fragrance, which may be declared as fragrance. The reasoning is trade secrecy: a scent formula is the most copyable thing a company owns.

The consequence for a reader is that the ingredient list is complete and accurate and stops precisely where your question starts.

Europe goes further than the US here, requiring certain fragrance substances to be named separately once they exceed a threshold, which is why European ingredient lists carry names like limonene and linalool at the end. That is the same product, labelled to a different rule, and if you can find a European version of a product you already suspect, its label tells you more.

The substances that actually cause it

The European baseline patch test series is a good guide to which ones matter, because it is assembled from what people actually react to.

It includes fragrance mix I at 8.0 percent, made up of named constituents: cinnamyl alcohol, cinnamal, hydroxycitronellal, amyl cinnamal, Benzyl salicylate’s relatives geraniol, eugenol and isoeugenol, and oakmoss absolute. Myroxylon pereirae resin, better known as balsam of Peru, is tested separately at 25 percent.

A short list of names does most of the work, and they are the ones worth learning to recognise on a European label.

The part almost nobody knows: it gets worse with age

This is the most useful thing on this page.

Limonene and Linalool are not strong allergens as such. Their oxidation products are. Exposed to air and light, they form hydroperoxides, and those are what sensitise.

The ESCD guideline records that “limonene and linalool hydroperoxides have recently been found to be more common in the younger age groups, which underscores the burden of fragrance sensitization”.

Two practical consequences follow, and neither appears on any label.

An old bottle is more allergenic than a fresh one. The same product, unchanged, becomes more likely to cause a reaction the longer it has been open.

A citrus oil is not gentler than a synthetic. Limonene is what makes citrus smell of citrus, and a natural essential oil is a delivery system for it. Natural fragrance is not a hypoallergenic category, and for this specific mechanism it is often the worse choice.

The wording on the front

Fragrance-free should mean no fragrance was added. It is not a regulated term in the US.

Unscented frequently means a masking fragrance was added to cover the smell of the raw materials. It is close to the opposite of what it sounds like, and it is the single most misleading word in this category.

Natural fragrance is not a safety statement. Essential oils are fragrance, they contain the allergens above, and they oxidise.

If you are trying to work out what it is

Keep the product that caused the reaction, and keep the label. Patch testing works from a list of suspects and the actual product is the best one you have.

Buy small and buy fresh, given the oxidation problem. A large bottle of something scented, used slowly over two years, is the configuration most likely to turn on you.

And treat a reaction to one scented product as information about that product rather than about all fragrance, until a patch test says otherwise. Fragrance is dozens of substances, and reacting to one of them does not mean reacting to all of them.