What to do if you have a reaction to a cosmetic product


I was disappointed with the way Watchdog handled its coverage of methylisothiazolinone. Quite apart from the blatant sensationalisation and lack of explanation, it also failed to address a pretty key question.  What do you do if you develop a reaction to a cosmetic product?

An allergy is something that any of us  can develop at anytime to anything.  But there are a few things that really seem to cause a lot of skin reactions.  One of the most common is nickel.  This obviously has nothing to do with cosmetics but it is worth pointing out that nobody knows what it is about nickel that makes it so allergenic.  If nickel had just been discovered no chemist would predict that an unusually high number of people would develop red itchy rashes to it.

Nickel allergy means that the sufferer needs to be careful in their choice of jewellery and clothing, but otherwise is not too bad a condition to have.  Food allergies on the other hand can be very serious indeed.  Although the bulk of allergic reactions are relatively mild, there is always the chance of an extreme one which might put you in hospital and very very rarely might kill you.  Nut allergies are something we all know about because activists have persuaded every conceivable source of nut contamination to prominently label the risks.  (At least they have in the UK – You can’t visit a supermarket here without being warned over and again which products might contain nuts.)

In the overall scheme of things allergies to cosmetics are one of the least troublesome manifestations of this problem.  Cosmetics are used in small quantities, and most of what is applied never makes it across the skin.  Formulators have learnt to avoid ingredients that have a tendency to cause lots of allergies.  On top of that there is industry wide co-operation to minimise reactions to known allergens.  (More on that later.)

As a result, the total number of reactions to cosmetics and personal care products is pretty low.  As far as I know there has never been a death due to an allergic reaction to a cosmetic product. It is a theoretical possibility, but has probably never happened.

But while the overall percentage is low, of course if you are one of the unlucky ones who does get a reaction, you are affected 100%.  Knowing you are in a small minority won’t be too much comfort.  So what do you do if you have reaction to a cosmetic product?   Lets look at the science.

Allergic reactions are caused by your immune system identifying something it encounters as a problem.  We all have the potential to develop an allergy to just about anything at just about any time. The most extraordinary example I have heard is Stephen Fry.  He reports that he is allergic to champagne.  He describes being taken to hospital on one occasion and missing a ball as a consequence.  Champagne allergy is a fairly rare one, and unless champagne becomes an item of mass consumption is unlikely to become one.   You need a reasonable level of exposure to the allergen for the allergy to develop.

Another surprising allergy is when the body actually becomes allergic to bits of itself.  This seems to be at last a part of what happens in the case of eczema.  The technical term is autoimmunity.  But back to the skin.

In the case of a skin allergy what happens is that the agent crosses the skin where it encounters the white blood cells.  The white blood cells will latch onto to a particular shape of molecule which they interpret as a threat.  This might not be the whole molecule, it might be a portion of it.  In fact might be the result of a reaction between the allergen and a protein in the skin.  But what happens next is that the body reacts as if it is being attacked by something foreign.  Blood vessels expand to allow the white blood cells easy access to the site of the attack.  This is why the skin goes red – the scientific term is erythema.  Lots of inflammatory agents are released that are intended to destroy the perceived aggressor.  The skin feels hot and itchy in a form of collateral damage.

There isn’t much rhyme or reason to which materials are most likely to cause allergies, but some seem to be a lot more prone to it.  Common causes are preservatives.  Two of the most commonly experienced allergies are to the parabens and methylisothiazolinone/methylchloroisothiazolinone.   This is because these two agents are very widely used.

Paradoxically, they get used widely because they don’t cause many skin reactions.   If you ship millions of units, as big cosmetics companies do, you will get reports back of allergies.  These get taken seriously and if an ingredient is identified that is causing a lot of allergic reactions it gets formulated out.  All the companies end up converging on the same low allergen inducing alternatives – which in practice means the parabens and the azolinones.   This is fine for most of us, but gives the small number of people who are allergic to them a real problem because they have so few alternatives.

Other preservatives, especially the organic acids in my experience, are also quite likely to be culprits.

Here is a list of the most common ones.  They are very very roughly in order of how widely I think they are used.  Do remember that paradoxically you are probably more likely to react to something that is less widely used and lower down the list.  (Fellow formulators are very welcome to dispute my assessments of relative used levels.)

Methylparaben, ethylparaben, propylparaben and butylparaben



Sodium benzoate

Benzoic acid

Dehydroacetic acid

Potassium sorbate

Sorbic acid

Sodium dehydroacetate




DMDM Hydantoin

Benzyl alcohol


Diazolidinyl Urea

Iodopropynyl butylcarbamate

Those are the most commonly used ones.  There are quite a few more that are approved for use but which are so rarely encountered I have kept them off the list, which is probably already too long.

Fatty acids also affect some people in a way that has always seemed very strange to me.  The most common fatty acid involved is stearic acid, but myristic acid, palmitic acid and oleic acid can also cause reactions.  This is strange because these are all commonly found in food and yet I can find no accounts in the literature to people reacting to eating them.  The reaction is also highly dependent on the formulation, making it a hard one to track down.

Food colourings are controversial and luckily I don’t have to get into that here.  But colourings in cosmetics very very rarely cause any allergic reactions, so that at least can be ignored.

Fragrances and essential oils are typically packed full of components that have form as allergens.  This fact has been recognised in the EU legislation which requires the 26 most commonly encountered allergens to be specifically listed.  This is a good pragmatic approach because both fragrance and essential oils can possess quite a lot components and it would quickly become impossible for them all to be listed on the ingredient lists.

You will see these fragrance allergens on any number of products.  But in fact allergies to these are not all that commonly encountered.  The reason for this is that there is a code of practice controlled by an organisation called IFRA- the International Fragrance Research Organisation – which publishes and continually updates guidelines on how to formulate fragrances.  These aren’t compulsory but almost every significant company follows them.  This is one of the cosmetic industries best kept secrets, and it is a shame that more people don’t know about it.  I may do a blog post on it in the future.

But even so, the list of allergens is worth referring to if you have experienced a reaction.

Here is the list in full.

Amyl Cinnamal

Benzyl Alcohol

Cinnamyl Alcohol





Amcylcinnamyl Alcohol

Benzyl Salicylate




Hydroxyisohexyl-3-Cyclohexene Carboxaldehyde

Anise Alcohol

Benzyl Cinnamate


Butylphenyl Methylpropional


Benzyl Benzoate


Hexyl Cinnamal



Alpha-Isomethyl Ionone

Evernia Prunastri Extract

Evernia Furfuracea Extract

So you now have a list, probably slightly longer than you wanted, of potential allergens in the cosmetic product you are having issues with.  You might now be able to spot the ingredient that is giving you trouble just from comparing the lists of products which give the problem and those that don’t.

A few points though – although very low levels of an allergen can provoke a reaction there is still a minimum level that is needed.  If an ingredient is present on a pack list, it might well be there in vanishingly small quantities.  So even if you discover you are allergic to say limonene you might well find that not every product that contains limonene is an issue.

Also different formulations affect the way things work.  I am sensitive to potassium sorbate myself for example.  But only to a relatively high level – higher than is normally used – and only in certain formulation types.  At normal use levels in a skin cream I am fine with it.  In fact if it weren’t for my job I would never have known.

So if you are trying to pin down the cause of your problem do bear in mind that it may not be completely straight forward to get to the bottom of the problem.   One thing that can help is going to a doctor and asking for a patch test.  This involves deliberately applying small quantities of known allergens to patches of skin on the back.  This is a standardised test which allows dermatologists to compare their data with each other.

Like any other test, particularly biological ones, you need to bear in mind that it has some shortcomings.  For a start the ingredients are added on their own, so you miss out on interactions between the ingredient and the formulation.  They are also applied at levels higher than they are normally used.   These shortcomings are inevitable given what the patch test is trying to achieve, but they are worth bearing in mind.  For example if I was patch tested I would no doubt show up as sensitive to potassium sorbate, even though I know that there isn’t a product on the market that I couldn’t tolerate.

The patch test protocol makes false positives more likely – quite rightly – but it can also give a false negative.  It is possible that the allergic reaction will only occur in the presence of another agent that encourages it to be absorbed across the skin.  The skin is in general a good barrier but there are exceptions.  Quite a few of the fragrance allergens for example will readily cross the skin and might well do it even more efficiently if they have been solubilised.

So if you are unlucky enough to suffer from an allergic reaction I hope this has helped with your detective work.  I’d love to hear of any experiences you may have had that might help other sufferers.  And if you haven’t had any trouble with allergies yet, don’t feel too smug about it.  It is something that can develop more or less any time and there is no way of knowing when.

So whether or not you have an allergy, Good Luck!

18 thoughts on “What to do if you have a reaction to a cosmetic product”

  1. Colin, as you might expect, I will take issue with your assessment on the relative frequency of response to parabens compared with other common preservatives. It is clear to me that methylisothazonline has recently become the most prevalent cause of contact allergy, but parabens are way behind in terms of the % of dermatological patients suffering such a response, and they are way behind sorbic acid also. It’s difficult to be precise on relative rates of sensitisation, because few studies analyse data from more than a handful of clinics at any one time, but parabens have, historically, been around the 2% area, which I will emphasis as being 2% of dermatology patients, NOT 2% of the general population (and, therefore, significantly lower in the general population).

    Frequency of preservative use data are available for the USA and Canada, and are notified to the FDA and published in Cosmetics & Toiletries by David Steinberg. Whilst this obviously only reflects the North American usage, a broad assumption may be made that there will be little significant difference for usage in the EU. Parabens (methyl and propyl) are still way ahead of all other preservatives (although the gap has closed somewhat in more recent years), but phenoxyethanol is next on the popularity list, followed by butylparaben, ethylparaben, sorbic acid/potassium sorbate, isothiazolinones, DMDM hydantoin, imidazolidinyl urea, benzoic acid/sodium benzoate, diazolidinyl urea (based on 2010 data). All other preservatives were used in fewer than 1500 different products in that year. For a little more context, methylparaben was present in 13,434 different products (out of those notified – it’s a voluntary scheme, but has been taken up by the majority of the industry), whereas sorbic acid/potassium sorbate was in 2493 products. Given the continuing massively widespread usage of parabens, it is quite remarkable that they continue to elicit sensitisation at such a relatively low rate.

    1. Thanks Dene. I don’t think I can have been clear enough, but it is a point I have made quite a few times job the blog. Parabens have a very low level of skin reactions, especially when you consider how widely they are used. This article is aimed at people who have experienced a skin reaction, so it has to reflect the fact that although the rate of incidence is low the number of reactions is still high. The list of preservatives is in my idea of how frequently the preservatives are used, not how many reactions there are. Most consumers won’t be able to spot the preservative on the ingredient list. That is why I listed them. It wasn’t meant to be a rogues’ gallery.

      Now we are down the bottom half of the internet where not many people go I’ll share with you my idea that the industry should look at what IFRA have done really successfully to minimise fragrance allergies and see if we can do the same for preservatives.

  2. Good idea to have similar rules for preservatives as already exist for fragrance.

    I’ve seen a few companies that don’t list preservatives on the INCI, instead claiming they are fragrance, so fall under the parfum loophole.

    Would also be good to have rules for preservatives like Grapefruit seed, Japanese Honeysuckle, Bitter Orange and the other natural sounding ones that no-one knows the actual components.

    Perhaps also a standard way of alerting people with formaldehyde allergies to those preservatives that release formaldehyde over time?

  3. Patch testing changed my life. I completely back your advice to those experiencing eczema/dermatitis to get patch tested. After several years of worsening eczema and dozens of prescriptions for emollient and steroid creams I was finally referred to a dermatologist.

    Unfortunately, I am one of the unlucky ones allergic to parabens. My test was highly positive for parabens (and also colophony which I don’t see mentioned above, but is apparently quite a common allergen). I was so highly positive it was difficult to read the surrounding test patches and the local reaction to these two substances took me months to get over. This discovery was particularly important for me as several of the emollient creams the gp had been getting me to slather over my entire body contained parabens. I stopped using all products with parabens and my skin began to improve. I have been almost completely free of any problems for over three years now.

    I often wonder how many people with chronic eczema are simply allergic to one or more common ingredients but never get tested. I cannot stress enough how much eczema can effect every aspect of a person’s life: from sleeping and intimate activity to fashion and holiday choices. I always enjoy your blog and I thank you for raising awareness of this issue in a balanced and scientific manner.

    1. Thanks for sharing that experience M. The trouble with being allergic to parabens is they are so ubiquitous it is hard to spot the cause and effect. Having worked on eczema products, I don’t think eczema patients in general are particularly more susceptible to paraben allergy than anyone else. I think your experience is the more typical one – people get characterised as eczema sufferers because of their reaction to parabens.

      If you are interested colophony is an ingredient that used to be used in nail varnishes. It had two big disadvantages. It caused a lot of allergies. Also it is an absolute pig to process. The solvents you need to use to dissolve are so flammable you have to weaken the roof where you handle it so that if it explodes the force goes upwards harmlessly. It is still used for some pharmaceutical applications and there is some use that musicians have for it the details of which escape me at the moment.

  4. Thank you for your response. Agreed, it’s a difficult problem! I suspect the problem of paraben allergy is probably underestimated due to misdiagnosis and the fact that a reaction can trigger eczema in susceptible people. Because parabens are contained in so many products that are used all over the body, it is difficult to spot as a contact allergy. Unfortunately, there are too few dermatologists in the UK and many sufferers of mild to moderate skin problems never get referred.

    Colophony pops up in all sorts of places: violinist’s rosin, pears original soap, some leg wax (both hot and cold), elastoplast, Mr Sheen polish, soldering flux, Christmas trees, and hold-up stockings just to name a few!

    I too look forward to some stuff on fragrance guidelines.

  5. Thank you Colin, nice post. In regard to the purported EU allergens, I agree that red-flagging the most common allergens in fragrances is a sensible approach in theory. However, I can’t agree that the EU list does this, since the allergenicity of these compounds varies as much as 100-fold, and quite a few of them are not allergens at all. This has already been debunked by some dermatologists, although the SCCS continues to pursue an agenda which seems destined to regulate most essential oils out of existence, even though clinical relevance is often not demonstrated. I refer you to the third preview window on this page http://roberttisserand.com/essential-oil-safety-book-second-edition/ which shows the relative allergenicity of the purported EU allergens found in essential oils as determined by patch testing. Patch testing is, as you point out, somewhat unreliable, but I think does a good job in identifying relative risk. I have much to say about IFRA guidelines, but maybe some other time!

    1. Thanks for your comment Robert. You could probably write a much better article on this subject than I have. In fact you have probably already done so. I think allergic reactions are themselves unreliable and inconsistent, so any attempt to measure them let alone minimise them is not going to work as well as we would like.

  6. In regards to a comment early in your piece that you know of no deaths from the use of cosmetic ingredients, I recall something I read in an skin care trade magazine (sorry I can’t remember which one) a number of years ago. Although the product may not be an actual cosmetic, I thought it worth mentioning. A spa performed a seaweed wrap on a client who had a seafood allergy. Long story short, due to being left alone for a lengthy period of time, and lack of quick reaction from the spa, the client died. I know this sounds like an extreme case, but as a spa worker, it seemed like a good idea to put that out there for anyone reading your blog who performs that type of service.
    Thanks for the post, well done!

    1. Thanks for that Judy. I just did a google and came up with this


      This report suggests that it was something about the treatment that killed her, but your version is a lot more believable. Seaweed allergy isn’t common, or at least I have never come across it despite once specifically searching the scientific literature for reports of it. But as I said anyone can develop an allergy to anything anytime. From now on I am going to have to quote this story when the question of cosmetic safety comes up.

  7. Very informative. As someone with extensive allergies who has a LOT of reactions to cosmetic and skincare products, it’s potentially useful info. Although parabens don’t seem to bother me at all. Fragrance, however, is a biggie.

    As a lot of my allergies are to ‘natural’ ingredients, I can tell you that there is a distinct difference in the way my body processes something that is on my skin versus ingested. For example, one of my worst contact dermatitus reactions is to chamomile and its derivatives, but for a long time – some twenty years – I could still drink chamomile tea with no problem. This has changed in recent years and I can’t tolerate it orally anymore either, but it has been quite a separate thing.

    I tend to give skincare people a bit of a panic as to what to recommend to me, when I tell them I have extremely sensitive skin but I’m allergic to chamomile and rose and really, anything that’s flower-derived, plus allergic to most fragrances, and a handful of other things besides. And, yes, you are absolutely correct that sometimes it’s the interactions between ingredients that will give me a reaction, and those are bloody hard to track!

  8. Thanks for the article and the lists! I’m allergic to many ingredients, mostly scent ingredients. Lately more and more products contain phenoxyethanol as an alternative to parabens. I think this could be a reaction to the anti-paraben fad/panic. Unfortunately for me, I’m allergic to phenoxyethanol, not parabens, so it limits the products I can use. To make it worse, phenoxyethanol has a rosy scent, but since it’s a preservative, it can be used in “fragrance-free” products, to make them smell good. That makes many fragrance-free products unavailable to me! I think its use as a stealth scent could be another indirect result of cosmetic-ingredient panic. As with wheat-allergy, which is real but also trendy so a lot of people imagine that they must avoid wheat even if they aren’t allergic to it, I speculate that a lot of people think they are allergic to all fragrances, but aren’t really, and still want their products to smell nice, so they will buy “fragrance-free” products that smell nice and rosy, or “natural” “fragrance-free” products that have tons of aromatic plant essences listed as actives rather than as fragrances. In the grand scheme of things, my little scent allergy is not tragic, but it does lead to me having crazy-frizzy hair and occasional red eyes and wasted dollars.

  9. Hi Colin

    Interesting that you say nickel allergy has nothing to do with cosmetics. I’ve recently been trying to track down what is causing the redness and sensitivity on my face and have found that an ingredient in a product I’ve been using for years, PEG 40 hydrogenated castor oil, is hydrogenated in the presence of a nickel catalyst. I think I’m very sensitive to nickel but have also started to think I’m sensitive to castor oil, as I react to a number of lipsticks which contain it in high quantities. I also reacted badly recently to another product by the same company (new face serum launched with much hoo-ha by a much-loved botanically based brand) and see that the third ingredient is heptyl undecylenate, which I have discovered is derived from castor oil. Would be interested in your thoughts on this?
    Many thanks

    1. I have never heard of anyone being allergic to nickel having a problem with ingredients made with a nickel catalyst before. It doesn’t seem at all likely, but you never know with allergies. The same process that is used to make hydrogenated castor oil is also used to standardise quite a few ingredients – shea butter for example. If it were the nickel that were causing the problem I’d expect you to have rather more widespread problems. Another possible explanation is that the product containing the PEG 40 hydrogenated castor oil is reducing the barrier function of your skin and making you more prone to an allergic reaction to something else. If your botanical brand actually uses a lot of botanical material – most don’t – then it might well be the case that either the plant extracts contain some metals to which you are cross sensitised or that they have something else to which you are reacting. Reactions to plant extracts are rare but are certainly not unknown.


      But unfortunately all I can say for sure is that allergic reactions are often quite complex and that even with medical advice and patch testing it can take some time to get to the bottom of.

  10. Thanks Colin, that’s very helpful. I seem to be having some degree of success by switching to products without fragrance (I very much miss the fragrance of the lovely essential oils but think perhaps my facial skin is better off without them). What do you think of Paula Begoun’s uncompromising view that nobody, but nobody, should use fragranced skincare as it without fail causes inflammation, irritation and damage to skin?

    Best wishes

    1. I don’t think fragrances are particularly high risk, though if you have sensitive skin it might be worth steering clear of them.

  11. Thanks for this article! I am a 18 year old girl and I just recently started struggling with what is suggested as an allergic reaction. It keeps reoccurring after I’m limited the use of everything on my face (It presents as swollen, itchy, red eyes with a rash around the eyes) and I only use 2 products on my face now. I’ve been to several doctors and they all say eyelid contact dermatitis but I can’t really identify what product or ingredient is causing it so I began to do my own research and this article really helped shed light on some ingredients that I have been seeing in quite a few of the products I used to use.

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