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Shampoo Allergy: A Closer Look at Propylene Glycol

Propylene Glycol as a Shampoo Allergen

Propylene glycol is an ingredient commonly found in shampoos and cosmetic products in general. It acts as a solvent for many other ingredients including preservatives, fragrances and chemicals. It also acts as a humectant (meaning that it attracts water), and has some antimicrobial properties.

PG can act as an irritant and sometimes a true allergen. Irritant reactions are far more common; however allergic reactions have been well appreciated for several decades.

Studies by Zirwas and colleagues showed that propylene glycol was the fifth most common allergen in shampoos - found in 38 % of surveyed shampoos.
 

Reference

Skin reactions to propylene glycol.
Hannuksela M, et al. Contact Dermatitis. 1975.

Zirwas M, et al. Shampoos. Dermatitis. 2009


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Shampoo Allergy

Allergy reduced.png

Reduced Allergen Shampoos

With this post, we complete our week long look at shampoo ingredient allergies. Of the 10-30 ingredients that are present in modern shampoos, it's possible to be irritated or allergic to one of the components.  Diagnosing a true shampoo allergy is not easy as patients don't necessarily present to clinic with a red scalp immediately after using a shampoo. Rather patients with sensitivities to an ingredient in shampoos may present with dermatitis of the eyelids, neck, ears, face, back ... and sometimes (but not always!) the scalp.

This week we have focused on the top five allergens in shampoos. Of 179 shampoos analyzed in a study by Zirwas and colleagues, 170 had fragrance, making it the most common allergy. CAPB was second palace allergen (53 %), MCI/CI was third place (51. 4 %), formaledye releasers were fourth (48 %) and propylene glycol was fifth (38 %). Vitamin E and parabens are sixth and seventh.

About 1-4 % of the population has fragrance allergies and the incidence of fragrance allergy is increasing.  Given the large proportion of shampoos that have fragrance it can be quite difficult to find a shampoo that does not have fragrance.

Not everyone needs to change their shampoos. The vast majority of people do not have problems with common shampoos. However, if there is any suspicion that an ingredient in a shampoos might be irritating or causing allergy, a switch to an low irritant - low allergen shampoo might be considered. Consultation with a dermatologist who specializes in contact allergy would also be appropriate in many situations.

Interested individuals may wish to review our website for our handouts on shampoos that don't contain fragrance and shampoos that are devoid of ingredients like CAPB, MCI/MI, formaldehyde releasers and propylene glycol. This information is available at www.donovanmedical.com/shampoos.

With that we end our week long look at potential allergens and irritants in shampoos!


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Shampoo Allergy: Top Allergens

#4 Formaldehyde Releasers

Allergy 4.png

Formaldehyde-releasers (FDRs) are the fourth most common allergen in shampoos. Studies by Zirwas and colleagues showed that 48.6 % of shampoos contained FDRs. 
FDRs are used as antimicrobial and antifungal preservatives in a wide variety of cosmetics and hair care products. They are called “releasers” because these chemicals slowly release the chemical formaldehyde as they break down and such release can cause irritation or allergic contact dermatitis.

In the right circumstances these FDRs can release formaldehyde in concentrations exceeding 200 ppm.

There are well over 40 FDRs but the 7 most common are: 
DMDM hydantoin
Imidazolidinyl urea
Diazolidinyl urea
Quaternium-15
Bronopol
5-Bromo-5-nitro-1,3-dioxane
Sodium hydroxymethylglycinate
 

Reference

de Groot A, et al. Contact Dermatitis. 2010.

Zirwas et al. Dermatitis 2009.
 


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Shampoo Allergy: Top Allergens

# 3 MCI/MI

Methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) are two separate ingredients but frequently used together at a ratio of 3 parts MCI to 1 part MI in preservatives. MCI/MI is commonly used in cosmetic and industrial applications.

shampoo allergy 3.png

Interestingly, MCI and MI were initially introduced in the 1980s in various occupational applications – in glues, paints, and cleaners as a mixture.  Since 2005, it has been more widely used in cosmetics, sunscreens and household products, such as moist wipes, shampoos and conditioners.  It’s also found in cleaners and liquid laundry products and household cleaners.



The world is likely become more sensitized and allergic to MCI/MI. Some reports have shown an increase in sensitization to MCI/MI and MI by itself.The global frequency of sensitization to MCI/MI remained constant at around 2.1% from 1998-2009, but increased to 3.9% in 2011. In shampoos, it represents the third most common allergen after fragrance and cocamidopropyl betaine. 51.4 % of shampoos contain MCI/MI.

Many countries have changed their regulations on how MCI/MI can be used. Interested individuals should contact local authorities as regulations differ from country to country.

The general trend is a recommendation to ban MCI/MI in leave on products and allow it in rinse off products at tightly regulated concentration levels. In Canada, an alert was issued stating that “after June 14, 2016, all products intended for use by children under the age of three that contain MI/MCI should no longer be available for purchase. All other leave-on products containing MI/MCI were longer available for purchase after December 31, 2016.

In Canada, MI is allowed as a preservative at a maximum concentration of 0.01 %. MCI is no longer permitted in leave on products but is accepted in rinse off products at a maximum concentration of 15 ppm (0.0015%) This 15 ppm is the typical threshold in most countries.

 

Increasing trend of sensitization to Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI). 

REFERENCE

1. Scherrer et al. An Bras Dermatol. 2014 May-Jun; 89(3): 527. 

2.  Geier J, Lessmann H, Schnuch A, Uter W. Recent increase in allergic reactions to methylchloroisothiazolinone/methylisothiazolinone: is methylisothiazolinone the culprit? Contact Dermatitis. 2012;67:334–341.  

3.  Mowad CM. Methylchloroisothiazolinone revisited. Am J Contact Dermat. 2000;11:115–118.  3. Lundov MD, Thyssen JP, Zachariae C, Johansen JD. Prevalence and cause of methylisothiazolinone contact allergy. Contact Dermatitis. 2010;63:164–167.  

4. Urwin R, Wilkinson M. Methylchloroisothiazolinone and methylisothiazolinone contact allergy: a new epidemic. Contact Dermatitis. 2013;68:253–255. 


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Cocamidopropyl Betaine (CAPB): #2 Allergen in Shampoos

#2 Allergen in Shampoos

Cocamidopropyl betaine (CAPB) is an organic compound derived from two ingredients: coconut oil and dimethylaminopropylamine. It was the Johnson & Johnson company that introduced the first cocamidopropyl betaine (CAPB) detergent shampoo in the 1950s using coconut oil. This shampoo ultimately gained extreme popularity as the well known “no more tears” baby shampoo.

shampoo allergy 2.png

 

Cocamidopropyl betaine is a wonderful surfactant and creates a thick lather.  Surfactants are products that have both lipophilic (oil loving) - and hydrophilic (water loving) properties. These dual properties is what enables them to remove dirt and oil from the hair when used in a shampoo. Cocamidopropyl betaine typically doesn't cause much in the way of irritation which makes it a good choice.  For this reason it’s acommon ingredient in many liquid skin cleansers. When used in conditioners, it helps function as an anti-static agent.

Studies by Zirwas in 2004 showed that CAPB was present in 53 % of 197 shampoos that were studied. This made it the second most common allergen in shampoos, second only to fragrance. Tomorrow, we’ll review the third most common shampoo allergen.

REFERENCE

Zirwas M, et al. Shampoos. Dermatitis. 2009


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Fragrance Allergies: #1 Allergen in Shampoos

 #1 Allergen in Shampoos

fragrance.png

It's possible to be allergic to an ingredient in shampoos. Many patients with shampoo allergies don't develop scalp reactions as their main concern - rather they develop a range of dermatologic issues such as eyelid dermatitis, neck dermatitis and facial dermatitis.

Fragrance is the most common allergen in shampoos. Of 179 shampoos analyzed in a study by Zirwas, 95 % had fragrance. About 99 % of the population comes into contact with fragrance allergens during a given week and about 1-4 % of the population has fragrance allergies. They are added to shampoos (and other cosmetic products) to increase their appeal. Overall, the expert consensus is that the incidence of fragrance allergy is increasing around the world. 
The terms 'fragrance-free' and 'unscented' are often used interchangeably but mean very different things. Unscented is a somewhat meaningless term but does indicate that the product does not have a strong odour. An unscented product could actually be full of fragrance but the fragrance dampens down some objectionable smell to create an overall neutral smelling product.  A patient with a fragrance allergy could have a serious reaction to an unscented product but not to a fragrance-free product.  Legal regulation over use of the term unscented has not yet occurred.

In the US, the terms fragrance are used to denote a product containing any one of many fragrances. In Canada, the term fragrance/parfum is used. North America is behind the times when one compares regulations in Europe. In Europe, it is now mandatory to report and disclose 26 fragrance ingredients in products.  Manufacturers can no longer simply label the product with the generic term 'fragrance.' Some North American companies are following suit and disclosing the exact fragrance allergen, but the process has been slow. 
In summary, fragrance allergens are the most common allergen in shampoos. Individuals with concerns about fragrance should look for shampoos that are fragrance free.
 


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Shampoo Allergies: Look Beyond the Scalp!

Look Beyond the Scalp!

shampoo allergy.png

It’s possible to be allergic to the shampoo one is using. This week we’ll talk about this important topic. It’s often forgotten about.

Shampoo allergy is not easy to diagnose. Patients don’t simply develop any itchy, red scalp right after they use a shampoo. Rather individuals who are allergic to an ingredient in their shampoo may develop rashes elsewhere including the eyelids, face, ears, neck and back. Of course the scalp can be involved but often not right away. 
Even patients who think of the possibility find that when they change their shampoo the problem does not go away. Often that is simply because the next shampoo also has the allergen.

This week we’ll talk about common allergens in shampoos including fragrance, cocamidopropyl betaine (main two we’ll discuss on Tuesday and Wednesday). Others include MCI/MI, propylene glycol, formaldehyde releasers and vitamin E.
 


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Anti-Dandruff Shampoos: Does resistance develop?

Does resistance develop?

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Dandruff and its closely related cousin seborrheic dermatitis are often chronic conditions which means that long terms treatments are needed. Anti-dandruff shampoos are typically viewed as first line agents. Many patients raise concerns that chronic use may be associated with development of resistance or some type of decreased benefit if continuously used. The proper term when something does not work as well with continued use is “tachyphylaxis.” So does, continued use of anti-dandruff shampoos give tachyphylaxis?

A 2009 study investigated the anecdotal belief that tachyphylaxis occurs in long-term treatment of seborrheic dermatitis and dandruff. Two double-blind, randomized, clinical evaluations were conducted, 24- and 48-week studies, whereby a 1% PTZ shampoo, a 2% PTZ shampoo, or a matched placebo control shampoo was used by each subject for the duration of the study. A questionnaire was also sent to dermatologists asking about their views of whether “tachyphylaxis” could really develop or not. Interestingly, Sixty-four per cent of responding dermatologists believed tachyphylaxis occurred with PTZ products, and most felt that tachyphylaxis occurred within 3 months of use. However the actual clinical data showed that there was no evidence for tachyphylaxis within 48 weeks of treatment. 
The conclusion from the study was that there was no evidence for tachyphylaxis in the treatment of seborrheic dermatitis and dandruff. It appears the advice many dermatologists give their patients about these agents is opinion based rather than factual.

Reference

Schwartz et al. Does tachyphylaxis occur in long-term management of scalp seborrheic dermatitis with pyrithione zinc-based treatments?
Int J Dermatol. 2009.


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Shampoos for Seborrheic dermatitis and Dandruff

Shampoos for Treating Seborrheic and Dandruff 

A variety of shampoos are available for treating dandruff and seborrheic dermatitis. The following is a helpful list we provide our patients. It includes both sulphate free and sulphate containing shampoos. To download the complete handout, click here. 

 

Anti-Dandruff Shampoos

dandruff shampoos

 

Sulphate Free Anti-Dandruff Shampoos

sulphate free dandruff

This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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How often should I use my shampoo for treating seborrheic dermatitis?

There are several good shampoos for treating seborrheic dermatitis. These include shampoos containing ingredients such as ketoconazole, selenium sulphide, zinc pyrithione and ciclopirox.

Most of the time, I start my patients on 3 times weekly use of these shampoos for anywhere from 2-5 minutes. Over time (and depending on response) we go down to 1-2 times weekly and sometimes every second week.  Please see a dermatologist to carefully review what is appropriate in your case.

Not everyone with seb derm responds to these shampoos. In such cases addition of a corticosteroid for a short period of time or use of an oral antifungal or oral retinoid may be appropriate.


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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What is "pityriasis amiantacea"?

Pityriasis amiantacea

Pityriasis amiantacea is not a diagnosis. Rather it is a phenomenon that sometimes happens to the skin and hairs during the process of inflammation. 

The finding of pityriasis amiantacea is often seen in patients with psoriasis, seborrheic dermatitis and various eczemas. 

The photo to the right is a magnified photo of the scalp of a patient with "pityriasis amiantacea" from psoriasis.

Treatment includes identifying the root cause. Treatment such as topical steroids, steroid injections, anti dandruff shampoos, salicylic acid, tar all play a role in treatment. 


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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To Poo or Not to Poo: A closer look at the “no poo” (no shampoo) movement

Should you give up shampoos?

If you’re like most people, you have a bottle or two of shampoo in your shower and you use it to clean your scalp and hair. Perhaps you’re a daily user, perhaps you use shampoos a few times week. If you have coarse and curly hair, you might use shampoo even less frequently.   But you use it. If my own practice is representative of the world out there I know some of you even change your shampoo brands frequently.

However, a small number of women (and an even smaller number of men) have decided to forgo shampooing the scalp altogether. This defines the so called “no poo” movement (i.e. ‘poo’ is short for shampoo).

  

 1. We are a shampoo loving society

As a society, we have grown to love shampoo and love shampooing. Walk into any drug store and you’ll see just how much real estate is devoted to shampoos. We love the smells of shampoos and the feel of shampoos. We love the look and feel of shampoo bottles. We like the shampoo aisles, shampoo ads and shampoo commercials.  We are a shampoo loving society.

Shampoos were first synthesized in the 1930s, as an alternative to bar types soaps which left a heavy film or “soap scum” on the hair.  Such deposition leaves the hair dull and more difficult to manage.  In years gone by, women  would shampoo their hair at the salon and then have it set. Shampooing every 2-4 weeks was normal. Shampooing wasn’t typically a home-based procedure. It wasn’t until the 1970s and 1980s that shampoos became standard for household daily use. In North America, many women have changed to shampoo their hair very frequently. Moreover, we seem to enjoy squeezing our shampoo bottles and in general use far too much shampoo with each use than we really need to. It’s not really harmful to do so – except to our bank. It’s too often forgotten, that shampoos are meant for cleaning the scalp and conditioners are meant for the hair. A small dab of shampoo is usually sufficient to clean the scalp.

 

2. If people don’t poo (shampoo), what do they do?

For those who are participants in the ‘no poo” movement and don’t use shampoos, common substitutes include simply using water alone, using apple cider vinegar, baby powder, dry shampoos or using baking soda.  I believe that many of such practices are well tolerated for most people. However, those with color treated or relaxed hair may find that that high pH of baking soda (up to 10-12) to be particular harsh on their hair and increase the chance of damage and hair breakage.  

 

3. Does frequent shampooing trigger your scalp to make more oil?

It’s true that the use of shampoo removes oils from the scalp. These oils are helpful to condition the hair – and might be regarded as nature’s best conditioners. At present, however, there is no scientific proof that the scalp compensates for frequent shampooing by in turn producing more oil. The amount of oil that our scalp produces is genetically determined, and to a much lesser degree by the foods we eat, hormones, seasons and the environment. Changing your shampoo practices won’t reset your oil production. That factory is deep under the scalp (in glands known as sebaceous glands) and not influenced by how you shampoo. It would be nice to think otherwise – but there’s simply no proof.

 

4. How often should you shampoo?

There is no magic number for how often we should shampoo. In fact, the number is different for everyone.  Those with fine, oily hair are going to benefit from daily shampooing as the oils tend to weigh down the hair. Those with coarse and curly hair can go much longer as the hair will actually look better when not washed so often.   The same is true for those with color treated or relaxed hair – washing less frequently is preferred to further limit damage to already slightly damaged treated hair.  Once or twice a week is likely just fine. Although we certainly shampoo our hair too often, washing the scalp daily is unlikely to cause harm. Furthermore, there is no evidence that avoiding shampoo altogether offers a health benefit. In other words, the no poo movement is a personal choice, not a health choice.

 

5. Are there any adverse effects of not shampooing ?

Individuals with existing scalp problems could develop a ‘flare’ of their scalp disease with cessation of shampooing. For example, I’ve seen many patients who forgo shampoos that develop worsening dandruff and seborrheic dermatitis ( which is a close cousin of dandruff). It’s usually mild and tolerable. To understand why this occurs, it’s important to understand that dandruff and seborrheic dermatitis are caused by yeast that lives on our scalps.  These yeast feed off scalp oils. Excessive oiliness from not shampooing provides this yeast with an abundance of food and in turn further exacerbates the patient’s scalp problem.  The no poo decision might not be for everyone.

 

6. If you’re going to shampoo, should you go sulfate free?

For those who decide that the no poo movement might not be for them, a common question then arises – what about joining the sulfate free movement? Certainly, sulfate free shampoos are popular. If you’ve used a sulfate free shampoo you immediately notice they don’t lather up quite as well as a shampoo containing sodium lauryl sulfate or ‘SLS‘. The main downside of these shampoos is not their lathering ability but the fact that SLS shampoos are a bit more drying and are more likely to lift the cuticle and cause damage for those with color treated or relaxed hair. The can also cause irritation for those with scalp problems, including eczema.  The vast majority of people in the popular will notice little difference to their hair from using a sulfate free or SLS containing shampoo.  Decisions on whether to use SLS shampoos for other reasons (including environmental) are still being researched. However, from the perspective of the hair – the vast majority of people will not achieve better hair care from sulfate free shampoos.

 

Conclusion: Are you giving up shampoo?

Hair is personal. Hair helps define who it is we are and how we present ourselves to the world. Our hair is central to our self identify. If you don’t want to shampoo your hair – don’t shampoo your hair. There are a small number (but manageable number) of risks. Similarly if you want to shampoo your hair frequently, shampoo it. Change up your brands.  Enjoy all that shampoos offer in further defining what is personal, individualistic and what defines our feelings of self identity and self-expression.  There are risks to many things and it simply comes down to being well informed.  Humans quickly learn what shampooing frequency is right for them.


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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The No Poo movement - Dr. Donovan interviewed on CHCH News

More Women going without shampoos

The 'no-poo' movement refers to a trend whereby shampoos are not used. Instead various non shampoo alternatives are used (water, apple cider vinegar, baking soda).

Dr. Donovan was recently interviewed on CHCH News 

See the interview here:

http://www.chch.com/the-no-poo-movement/


This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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Scalp Discoloration ... from a Shampoo?

SS ZP shampoo.jpg

When children Selenium sulfide (left) and zinc pyrithione (right) shampoosdevelop red-brown discoloration in the scalp, every pediatrician and pediatric dermatologist takes note. This is because red-brown scalps in children can sometimes be a worrisome sign of certain internal diseases. So you can imagine how puzzling it would for a group of four doctors in St. Louis, Missouri when six children in their practice appeared with red-brown scalps. 

What was the cause of the scalp discoloration?

Selenium sulfide anti- dandruff shampoos!

The doctors' discovery was very simple but very clever: and they published their findings in the journal Pediatric Dermatology.  It’s hard to say just how common this orange discoloration is from selenium sulfide shampoo, but it’s probably more common than we currently think.  There is nothing harmful about the red-orange discoloration from these shampoos, and the pediatricians showed the discoloration could  be removed with an ordinary alcohol swab and the scalp discoloration disappeared once the shampoos were stopped.

But it took clever minds to piece this all together!

Reference

Gilbertson K et al. Scalp Discoloration from Selenium Sulphide Shampoo: A Case Series and Review of the Literature. Pediatric Dermatology 2012. 29; 84-88.



This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.
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