05-10-2013, 02:23 AM
  • Mike D
  • Junior Member
  • Germany
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The Sensitive Subject of Allergens

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It is often seen on the label of cosmetic products "If irritation occurs discontinue usage". One may ask, why would a cosmetic company produce a product that would cause the consumer irritation? Causing the consumer irritation is not done intentionally. However because of the numerous chemical components that are found in cosmetic products and the broad spectrum of skin types and sensitivity of the consumers, there is a chance that a percentage of those purchasing the product will have an adverse reaction due to its usage. This adverse reaction can possibly be traced to a group of compounds collectively known as "Allergens".

Allergens are compounds that are capable of producing undesirable reactions through the normal immune system in people that are predisposed to respond to their presence. This predisposition is known as hypersensitivity and there are four classes that are categorized by the body's method of responding to the allergen. The mechanism that is responsible for the reaction from the exposure to allergens in cosmetic products places it in the catagory known as Type IV hypersensitivity. In this mechanism, known as cell mediated immunity, the allergens are taken up by a type of cell know as a macrophage. In the body it is the job of the macrophage to remove dying or dead cells, cellular debris and pathogens. In the case of the allergen, it will reappear on its surface of the macrophage in combination with a protein know as a major histocompatibility complex (MHC). In this combined configuration with the MHC outside the microphange, the allergen is able to be detected by Th1 cells, "Helper T-Cells", that have receptors sutiable for its recognition. The function of the T-cells are divrese because the various types (effector, regulatory and memory) function differently in response to the same allergen. To briefly sum up their function, they recognize the allergen as a threat to the body and send out a chemical signal (by producing cytokines, proteins or peptides) that tells the immune system that something harmful is present and needs to be delt with. The first exposure to the allergen causes the Helper-T cells that are sensitive to it to become activated and multiply. However it is on the second exposure to the allergen that the Helper-T cells respond by alerting the immune system of the threat. One of these alerts is to send a signal for an increase of the microphage concentration in the area to clean up the invading allergens and this results in inflammation of the skin.

An important part to note here is that a person has to be predisposed to this type of reaction for it to occur in this manner…in normal everyday language this predisposition is called "Being Allergic".

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Two other classes of adverse skin effects that are caused by topical exposure to substances are dermal irritation and dermal corrosion. Dermal irritation is defined as the production of reversible damage to the skin following the application of a substance for up to 4 hours. If the damage is not reversible then the injury is considered dermal corrosion.

The testing of a substance for its properties in these two areas was done in the past on laboratory animals. However with advances in technologies and diagnostic methods this is no longer necessary. Methods such as testing the reaction of substances on human cell cultures in the lab and also modeling the human skin system on computers are well past the development stage. Also the EU is progressively legislating a ban on cosmetic products that use substances that are tested on animals.

Just because a material is determined to be a corrosive, an irritant or an allergen does not prohibit its use in the production of cosmetics. Without the use of the corrosive materials sodium hydroxide (NaOH) and potassium hydroxide (KOH) the production of traditional shaving soaps would not be possible. It is these substances that are responsible for the conversion of the triglycerids in the fats and oils into the salts of the fatty acids that are commonly known as "Soap". In this process the negative OH ion, which makes the material so corrosive, is consumed in the reaction and becomes part of the glycerin molecule…which is a very good moisturizer for the skin. In the case of irritants, it is usually a question of the concentration in the finished product that is considered in the safety evaluation. It is for individuals who have allergic reactions or have sensitivities to the irritants below the threshold concentrations that are considered "Acceptable" that the sentence "If irritation occurs discontinue usage" is written for.

The method of testing to determine if a person has an allergy that responds in a type IV manner to a substance or if a substance produces an irritant response is known as a patch test. During a patch test a pad containing the suspected substance is taped on the skin for 24 to 72 hours. The dermatologists can also tell the difference between and Allergic reaction and irritation because not only do these two reactions have two different mechanisms through which the body responds to the substance, the appearance of the test area can also be different.

Sources of Allergens
In the EU all cosmetic products offered for sale to the public must undergo a safety evaluation of the ingredients to determine the possibility of adverse effects to the consumer. Traditional shaving soaps consist mainly of animal fat (Tallow), plant oils, water, sodium and potassium hydroxide, essential oils and perfumes. It is a relatively uncomplicated recipe when compared to other cosmetic products on the market. I cannot remember one instance of where allergens were listed as being in plant oil or tallow. Water usually does not even come into question. The sodium hydroxide and potassium hydroxide are not allergens but are hopefully sufficiently reacted so as not to produce detrimental effects to the skin. However, even though they usually make up less than 2.5% of the product by weight, the Essential Oils and Perfumes are usually the two largest sources of allergens in the traditional shaving soaps. Infact, some essential oils are just about all allergens…lemongrass containing the most. Below are some examples of the percentage of allergens in some of the more commonly used essential oils. The information is taken from the analysis of the essential oils I use in my soaps and creams.

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The carefull reader will have noticed that the lemongrass contains 101.55% allergens. I asked my supplier about this and was told that his analysis contains a range of the component in question. This is because the essential oils are a natural product and the concentration of the allergen in question varies with each batch. The content is over 100% because all the high limits of the range are listed.

There are two essential oils that contain no listed allergens and they are: Cedarwood and Sandelwood

Product Content of Allergens and INCI Listing
In Europe, the allergens are covered under directive 2003/15/EU. It is the responsibility of the manufacture to secure this information about the components of the product and present it to the safety evaluator for inspection.

In the process of shaving, the soap is used for the lather and then afterwards perhaps a lotion or tonic is applied. These products are viewed in two different classes as far as exposure calculations are concerned…the soap is a "Rinse Off Product" and the lotion is a "Leave On Product". For a "Rinse-Off-Product" all ingredients with a weight % greater than 0.01% must be listed on the label. For a "Leave-On-Product" the weight percent decreases by a factor of 10 to 0.001%.

To put some numbers to all this consider a shaving soap made with 1.9% lemongrass oil. This is enough to scent the soap quite strongly. The right column is the weight % of the allergens in the finished product.

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The list of ingredients need now be listed on the label according to the International Nomenclature for Cosmetic Ingredients (INCI) in order of their amount down to 1%. For any ingredient under 1% the "list in order of weight" does not apply. A note on INCI: The labeling is not written for the consumer but rather the doctor. To understand this consider the following situation… someone buys a product in Germany and takes it to Greece and has a reaction to it. The consumer goes to the doctor and shows him the container. If the ingredients were written in German and the doctor could not read German then he would not be able to suggest a treatment. To avoid this an international standard was agreed upon…INCI.

Below are the ingredients from the lable of my lemongrass bath soap with 1.9% Lemongrass oil in the recipe. The top list is in German for the customers and the bottom line is INCI for the doctors and the inspectors. Note that in the INCI only four of the five allergens in the lemongrass oil are listed.
Bestandteile: (Verseifte) Palmöl , Kokosöl, Sonnenblumenöl, Olivenöl, Süßmandelöl, Zitronengras Ätherisches Öl, Zitronengrasblätter, Mineral Pigment, Natrium Hydroxid, Wasser

Ingredients: nach INCI Nomenklatur
Sodium Plamate, Aqua, Sodium Cocoate, Sodium Sunflower Seedate, Sodium Olivate, Sodium Almondate, Glycerin, Cymbopogon Flexuosus (Oil), Cymbopogon Flexuosus (leaves) , Citral, Iron Oxide, Linalool, Geraniol Limonene

If this were an after shave lotion, a "leave-on-product", then the Eugenol, at a weight of 0.002%, must be listed because it is present in an amount greater than 0.001%.
Below is a link to a page listing the allergens and also to a nicely summarized download of the essential oils and the allergens that they contain.


It is to be seen that the percentage values in the down load for the essential oil allergens differ from the values listed above. This is to be expected when dealing with natural products and shows why an exact value for a substance in question in a natural product can only be obtained by analysis of the batch in question and is only good for that batch.

Special thanks goes to Churchilllafemme for information on the mechanism through which the immune system reacts to allergens.

Mike D

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0 29
 05-10-2013, 08:02 PM
  • Johnny
  • Super Moderator
  • Wausau, Wisconsin, USA
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Well done Mike.

180 24,733
 05-10-2013, 08:13 PM
  • Agravic
  • Emeritus
  • Pennsylvania, USA
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Very informative and enlightening, Mike. Thank you for detailing some of the complexities related to allergens, as well as the regulatory policies that are in place. The immune response pathway is fascinating in terms of variability between individuals.

102 18,709
 05-10-2013, 11:35 PM
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Interesting read, and I learned something new. Well done Smile

3 5,441
 05-11-2013, 05:43 AM
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Definitely helpful to learn some of the root cause of allergens.

0 24
 05-11-2013, 06:33 AM
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Nice job, Mike - lots of helpful information. Shout out to John as well for his helpful contributions!

73 4,346
 05-11-2013, 08:20 AM
  • freddy
  • Banned
  • San Diego, California, U.S.A.
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An excellent article. Thanks for doing this Mike. John, a great job with your input.

2 11,211
 05-11-2013, 09:03 AM
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Very interesting reading, thank you. Now I understand why I see what appear to be synthetic fragrances listed in the ingredients of products like Castle Forbes which are supposedly formulated only with essential oils.

15 773
 05-11-2013, 11:22 AM
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Interesting article, thanks!

0 82
 05-13-2013, 11:18 AM
  • mikeperry
  • Senior Member
  • St Louis via the UK
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Hi Mike

I'm going to have to read your article a few more times for it to begin making sense (I'm not the smartest cookie in the biscuit barrel) Blush

Thank you for taking the time to put the article together and share it here Thumbsup

And thank you John for sharing some of your expertise Cheers

Take care, Mike

23 1,872
 05-18-2013, 02:35 AM
  • Mike D
  • Junior Member
  • Germany
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Thanks fellows,

I am glad you are enjoying the article

0 29
 05-18-2013, 08:01 AM
  • geezer
  • Senior Member
  • Menomonie, Western WI
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Thank you for the information! I have been laid low with assorted sinus and bronchial problems by this spring's late coming and have been twice to the MDs. I am hypersensitive and hate to take medicines. There are few things which work for me so I have to remember them from year to year. There are particulate sensitivities which also do me in and those irritants such as unburned hydrocarbons in poorly adjusted vehicles and furnaces.
PS. Surprisingly, I seem to have no difficulties with 99% of the shave products I have tried. May you also be lucky!

8 1,194
 05-19-2013, 11:58 AM
  • Mike D
  • Junior Member
  • Germany
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Hi Richard,

The type of hypersensitivity that causes a reaction to pollen has a different reaction mechanism (type 1 hypersensitivity) than to the components in the essential oils (type 4 hypersensitivity). When I sent the first draft of the article in I wrote about the type 1 mechanism. Churchilllafemme, who is an expert in the subject of allergic reactions, spotted this error and directed me to the correct reaction mechanism, the type 4 hypersensitive reaction, for the class of allergens found in essential oils.

It is quite possible that because the immune system has a different reaction mechanism to pollen type allergies than to the components in essential oils, you do not have the same reaction to the shaving products as to the seasonal allergens.

0 29
 05-24-2013, 05:16 AM
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Mike, excellent article and great information.

Thanks! 5 Stars!

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