Seborrheic Dermatitis and Oil

Many sources state that using oils to moisturizer the skin is a big no-no for individuals prone to seborrheic dermatitis. But, during my time researching the subject, I’ve yet to come across specific data that confirms this statement.

This article attempts to review the relevant research and separate fact from fiction.

Hopefully by the time your done reading, you’ll have a better understanding of the relationship between oils and seborrheic dermatitis. Which ultimately allows you make more informed treatment decisions and keep your symptoms at bay.

Seborrheic dermatitis and malassezia

One of the most popular and persistent explanation for seborrheic dermatitis relates to the malassezia yeast. This connection has been described in great detail by numerous researchers in the past decade and previously reviewed in the underlying causes of seborrheic dermatitis section.

If you’re short on time for reading the above, the key piece of info relevant to this article is:

Malassezia is a family of yeasts that naturally reside on the skin surface and are present on the skin of most humans. In individual cases, they’ve been associated with several skin issues (one of which is seborrheic dermatitis). In seborrheic dermatitis, malassezia deposit oleic acid on to the skin surface, which in-turn causes the skin symptoms.

The oleic acid that is referred to above, is the same fatty acid that is found in olive oil. The key difference is that in olive oil, it’s present in it’s triglyceride form. And in this form, they are not considered irritants.

However, in their free fatty acid form (think of olive oil that begins to spoil), they can directly cause skin irritation while also increase it’s sensitivity to other irritants [1, 2].

What malassezia require for growth

To make better sense of it the relationship between oils and seborrheic dermatitis, let’s start with a review of what malassezia use for growth.

In the lab, to obtain optimal malassezia growth, researchers use the following composition [3]:

Bacteriological peptone – 10g, glucose – 10g, yeast extract – 2.0 g, ox bile, desiccated – 8.0g, glycerol – 10ml, glycerol monostearate – 0.5g, tween 60 – 5.0ml, olive oil – 20ml, agar – 5g, deionized water – 1.0l

Data source: Leeming & Notman agar Modified MLNA media – ATCC

From this, you can see that oil is only a small piece of malassezia’s preferred growth requirements. The remainder, is a combination of specific sources of carbohydrates, electrolytes, vitamins and trace elements.

But as this aims to achieve “optimal growth”, it may still be a poor representation of what malassezia’s minimal requirements are.

Digging deeper, we find that growth of a specific malassezia yeast, malassezi furfur, can be achieved with only two components: an amino nitrogen source and a lipid source [4]. In more common terms, a combination of almost any protein source (with the exception of Cysteine) and all oils beyond 12 carbon atoms are able to support its growth.

Eliminating oil to reduce malassezia growth

As a results of these two factors:

1. Prominence of the malassezia explanation of seborrheic dermatitis

2. Association between oil/lipids and malassezia growth

A lot of online/media sources quickly jump to the conclusion that oil is a big no-no for seborrheic dermatitis prone individuals (my-self having fall victim to this line of thinking for a long time as well).

But can it really be that simply? Is it really the oils that are to be blamed for seborrheic dermatitis? Can we really get rid of all oils that come into contact with our skin?

After all, our skin naturally uses oils for its protection. Surely we can’t get rid of all the oils present on it’s surface without really going out of our way.

So let’s dive deeper and try to clear things up.

The theoretical positives of oil elimination

The primary explanation as to why anti-fungal agents are so effective for the treatment of seborrheic dermatitis directly relates to their ability to prevent the growth of malassezia in the lab [5].

Since malassezia depend on lipids for growth, theoretically, we may be able to achieve similar results by simply making sure no lipids are present on the skin surface. This would starve the yeasts and prevent further growth. As the yeasts gradually die out, our symptoms clear up.

Sounds plausible enough.. Right?

But if this was the case, cutting out sebum production with an agent like isotretinoin (more commonly known as Roaccutane/Accutane) should lead to seborrheic dermatitis remission.

Unfortunately, it’s not this simple. In some cases, isotretinoin has actually been cited to lead to seborrheic dermatitis like skin eruptions [6]. To add to the confusion, going back as far as 1983, researchers have stated “Seborrhoea (excessive sebum production) is not a feature of seborrhoeic dermatitis”[7].

The consequences of oil elimination

Unfortunately, the above oil elimination theory/approach does not touch upon some very important factors, that greatly takeaway from its value.

First, consider the following:

• Certain areas of our skin utilize sebum for their protection
• Seborrheic dermatitis effects these sebum rich areas
• Roughly 58% percent of sebum is made up of triglycerides and fatty acids [8]

This means that as long as our skin functions normally, malassezia’s growth requirements are likely already met. So, right away, we know that completely starving malassezia of oils is not plausible considering normal skin function.

But what happens if we try to starve them?

Luckily, researchers from the University of Leeds have examined this line of reasoning and some interesting findings had emerged [9]:

• Malassezia yeasts utilize fatty acids in the production of a lipid outer layer
• Yeasts depleted of this layer cause a strong inflammatory response in skin cells
• An intact lipid layer inhibits this strong inflammatory response

To add to this, researchers from Korea investigated what influence detergents (shampoos, soaps, and cleansers – all fall into this description) have on this lipid layer [10]. These researchers found that:

• Common detergents can effectively strip the lipid layer of the malassezia yeasts
• Lipid depleted yeasts showed an increased ability to induce inflation
• Overuse of skin detergents may aggravate malassezia related skin conditions

Taken together, it becomes plausible that focusing too much on reducing the amount of lipids can ultimately have unintended consequences. Instead of starving away the malassezia, we may be unwittingly increasing their potential to induce skin irritation.

More sensible strategies to consider

If we presume that depleting malassezia of lipids is a poor strategy, we still have some other potential options to influence its lifecycle.

Keeping the skin pH low

An important characteristic of healthy skin is a pH level of around 5. At levels above this, malassezia have been shown to release significantly more allergens [11, 12].

Unfortunately, many soaps and shampoos drastically raise skin pH well beyond this optimal level and into the pH range of 6 to 10 [13]. Combine this with the lipid stripping properties of soaps and shampoos, a compounding effect can be presumed.

Sticking to pH balanced formulations, that aren’t overly aggressive, is likely to provide the most clear benefits on this front.

If your really keen on this, some dietary factors may also be worth considering as well (increasing Vitamin A and reducing monosaturated fats [14]).

Improving the lipid composition of our sebum

The sebum composition of seborrheic dermatitis affected skin shows significant differences in comparison to healthy skin. The biggest of these differences appears to be a reduced amount of unsaturated fatty acids [15, 16].

Inline with this data, aiming to improve the composition of lipids in our sebum could be the key to a more balanced co-existence with malassezia.

Though there aren’t any studies examining specific approaches, a combination of several adjustments:

• Dietary – quality/quantity of fats we consume and antioxidant availability
• Lifestyle – cardiovascular health
• Topical – direct application of specific oils

Is likely to provide the best mix of quick changes and help sustain long term progress.

In relation to the third point (topical application of oils), there is little data available on which oils are going to be the most beneficial.

However, based on the potential connection between oleic acid and seborrheic dermatitis, you likely want to avoid oils with the highest concentrations of this fatty acid (such as peanut, olive, and almond oils).

For reference, here is a neat fatty acid breakdown for you:

Avoiding abrupt changes

Another possibility is that abrupt changes in lipid availability could be integral to the flare/remission nature of seborrheic dermatitis symptoms.

While this is very much just a personal theory, please consider the following sequence of events:

• Lipids on the skin surface promote malassezia growth
• Soap usage abruptly strips the lipids away
• Lipid depleted malassezia are left on the skin surface and begin to trigger the immune response
• At the same time, the skin attempts to compensate for the depletion of lipids, by increasing sebum production [17]
• Your skin get’s oily and you reach for the soap once more

This cycle then repeats and what we’re left with, is the ups and downs of seborrheic dermatitis symptoms.

Based on the above, it’s plausible that by having more regular sebum outflows and reducing the fluctuations, the cycle can be avoided altogether. So next time you reach you go to wash your face, take the time to evaluate your habit.

Summary

When it comes to seborrheic dermatitis, definite answers are hard to come by. This article was my attempt at piecing together the relevant research and figuring out weather we should really be afraid of oils when faced with seborrheic dermatitis.

Here are the key points for your review:

Hope you’ve found this article useful and the ideas introduced can help you achieve remission.

If you have any experience using specific oils for seborrheic dermatitis, please considering sharing your experience in the comments section below. Any questions, suggestions, and concerns as welcomed.

Thank you for reading.