Anecdotal Successes
How I Got Severe SebDerm and Hair Loss under Control in Two Months
Latest Updates on 9 Oct 2023:
Hair shedding: shedding 10-20 hairs per day! back to my pre-sebderm level.
Hair thickness: GUYS my hair has grown back!!! back to my pre-sebderm hair thickness now!!! Personally, having a moderate amount of healthy carbs in my diet improves my hair shedding. I shed so much hair when I was on a low carb diet. My detailed hair growth routine is here: https://www.reddit.com/r/SebDerm/comments/173ktba/how_i_have_successfully_grown_my_hair_back/
Scalp conditions: healthy white scalp, no itchiness, no flakes
Shampoo routine: shampooing every other day, using Vichy Dercos Anti-dandruff Shampoo for Oily Hair every 7-10 days, Bioderma Node A Soothing Shampoo for the rest of the week.
Diet and Lifestyle: Mediterranean diet; go to bed before 12; 7-8 hours of sleep everyday;
Stress management: don't give a shit about things that used to bother me, overall better mood
Hi there, I've benefitted a lot from this community, so I'd like to make some contributions. I was losing an average of 200-300 hairs everyday at the onset of my sebderm. After two months, I'm now only shedding about 90 hairs daily, which is within the normal range. I know that clinically speaking there is no cure to sebderm and it may come back later, but I'm just happy that it's at least under control now. So I want to share this as my SOS protocol. As for long-term maintenance, I'm still learning so much about it from this community.
Background:
- suffered from dry dandruff (large and white flakes) for more than 12 years but never experienced any hair loss
- Because of COVID, I developed a bad habit of only shampooing 1-2 times a week (I have an oily scalp and straight hair). On non-wash days, I used a lot of hair products to keep my scalp feeling clean, e.g. scalp serum and dry shampoo. I only found out later that they contained denatured alcohol, which can destroy our skin barrier.
- In late Aug, I experienced increased hair shedding of a daily average of 200-300 strands when I usually only shed a maximum of 30-60 strands a day. At the worst point, I was losing 500 hairs when I was shampooing one day. And I almost passed out.
- My scalp was tingling, burning, and sore.
- I went to a dermatologist in early Sept. He diagnosed me with severe sebderm and folliculitis on my scalp. He said I needed to get my sebderm under control before he could treat my hair loss
- My before and after pics (warning: my sebderm was really bad on my scalp): https://imgur.com/a/jmhG46i
Sebderm and hair loss:
- I was very anxious and depressed about my hair loss because I've always had thick and healthy hair. People always give me compliments on how my hair looks. The point is that I was feeling so much pain mentally.
- I consulted other dermatologists. Some said sebderm could cause telogen effluvium because my condition was so severe that it shocked my hair. Some said even though sebderm could cause increased hair shedding, mine was too serious to be caused by sebderm alone. There might be other causes.
- But from Dr. Donovan's blog, there is a study that revealed that the more seborrheic dermaitits a person has, the more shedding (telogen effluvium) a person will experience. This tells us that individuals with severe seborrheic dermatitis are likely to have a severe telogen effluvium.
- I still went to my family doctor and a naturopath to get blood tests done just to be sure what we're dealing with here. Everything was normal, so I focused on getting my sebderm under control.
How I got the situation under control:
- My dermatologist prescribed me with clobetasol solution and ciclopirox 1.5% shampoo.
- At first, I was reluctant to use steroid. However, the longer my scalp stays inflamed, the more possible damage will be caused to my hair follicles, so I followed my derm's instructions and applied clobetasol to the affected areas daily for 21 days. My scalp was less red but I was still shedding 150-200 hairs a day.
- Using the ciclopirox 1.5% shampoo (every other day for 8 weeks, as instructed by my dermatologist) was not very helpful. After much research, I came up with my own protocol that has really helped me get my sebderm under control.
- What I found is key is that the protocol needs to consist of three components: 1) destroy the biofilm, 2) kill malassezia, and 3) rebuild skin barrier. For each component, there are numerous ingredients/products available.
- You can do all three components on a particular day or scatter them around throughout the week, depending on whatever suits your schedule and skin needs. Experiment and observe what suits your skin the best.
- An example of a three-component routine on a given shampoo day: 5% xylitol solution on the affected areas to be left on for at least an hour --> wash it off with an antifungal shampoo --> apply a malassezia-safe moisturizer
- An example of a three-component routine in a particular week (this is what I'm doing now): biofilm shampoo on day 1 and day 3 of the week followed by ciclopirox shampoo on day 5 and day 7. Each time after shampooing, apply a malassezia-safe moisturizer
- Some ingredients for 1) destroying the biofilm: xylitol, ACV, and selenium sulfide, MCT oil without lauric acid
- Some ingredients for 2) killing malassezia: ciclopirox, ketoconazole, coal tar, zinc pyrithione, and MCT oil without lauric acid
- Some ingredients for 3) rebuilding skin barrier: panthenol (vitamin B5), niacinamide (vitamin B3), glycerin, and aloe vera
- Salicylic acid is not anti fungal per se, but it's great at removing the scales, regulating sebum production, and calming down inflammation.
My detailed protocol:
- I shampoo four times a week: Selsun Blue 2.5% Selenium Sulfide --> Selsun Blue 2.5% Selenium Sulfide OR T/Sal --> Ciclopirox 1.5% Shampoo --> T/Sal (I only use Selsun Blue twice a week for 2 weeks when things are bad because it is very strong)
- This protocol is for short-term ONLY, e.g. 2-6 weeks! To get things under control first.
- (updated on 4 Jan 2022) As my sebderm is getting much better, I have switched to this gentler protocol, which again incorporates all the essential components, for long-term maintenance. I'm rotating three different shampoos: Neutrogena T/Sal, DermaKB Scalp Detoxifier (biofilm disrupter), and Philip Kingsley Shampoo for Flaky Shampoo (contains an antifungal Piroctone Olamine). To hydrate my scalp, I've been using a DIY niacinamide and panthenol spray.
- Selenium Sulfide 2.5% is a game changer for me!! The dandruff/biofilm was finally coming off after 1-2 uses. Antifungals cannot get to the malassezia to do their job if the biofilm is present.
- After shampooing, I apply a DIY 3% panthenol aloe vera gel to my scalp. I'm now using this DIY 2% glycerin, 2% panthenol, and 4% niacinamide in water spray.
- Avoid ANY ingredient that may feed malassezia (I use a website called Sezia. Simple Skincare Science is also a very good source).
- Even though I don't suffer sebderm on any other area, I switch all of my skincare products to seb-derm safe products because my skincare may transfer to my pillow.
- I use a silk pillow case to reduce the friction (I can't afford to lose even one more hair).
- I change my pillow case every 2-3 days and wash my pillow every week.
Product recommendations:
- What is weird is that a lot of the products that are supposed to be formulated for people with sebderm are not sebderm friendly. They contain ingredients that feed malassezia. There is a useful website called Sezia that I use to check whether a product is safe (not affiliated). This is also the reason I need to DIY the panthenol and aloe scalp treatment.
- Products that I like: Selsun Blue 2.5% Selenium Sulfide Shampoo, Neutrogena T/Sal, Philip Kingsley Shampoo for Flaky Scalp, dermaKB Biofilm Scalp Detoxifier, Philosophy B5 powder, the Ordinary 100% niacinamide powder,
- Products that made my situation worse: Head and Shoulders Royal Oils Scalp Elixir, Inkey List Salicylic Acid Scalp Treatment, Head and Shoulders Clinical Strength 1% Selenium Sulfide
- I will be experimenting with a DIY niacinamide and panthenol toner (for rebuilding skin barrier and calming inflammation) and 5% xylitol solution (for destroying the biofilm) and will keep this community updated of my results. After much trial and error, I settle on this DIY scalp toner (2% glycerin, 2% panthenol, and 4% niacinamide in distilled water, which I think is really helpful for calming my scalp.
- Neutrogena T/Sal shampoo may be too harsh for people with a dry/sensitive scalp, but my oily scalp loves it!!! It helps get rid of the oily buildup and flakes on my scalp while also regulating my sebum production. My scalp is definitely less oily. And malassezia loves an oily scalp because they also feed on our natural sebum.
Diet and supplements (Please see here for a detailed wholistic approach to tacking sebderm: https://www.reddit.com/r/SebDerm/comments/rggsrj/a_novelwholistic_evidenceinspired_approach_to/):
- Daily: Vitamin D3+K2, cod liver oil, reishi, homemade kefir, nutritional yeast, MCT oil
- 2-3 times a week: zinc, magnesium glycinate, and collagen powder
- What I would recommend for almost everyone: vitamin D3+K2, magnesium, and fish oil.
- Around 60-70% of people in North America are deficient in vitamin D. There are also studies that point to an association between vitamin D deficiency and inflammatory skin conditions such as sebderm. Although this does not mean a causal relationship, taking vitamin D3 overall can help regulate our hormones and immune system. Magnesium and vitamin K2 should be supplemented with vitamin D3. This combo also help me better deal with stress, which is also a trigger of sebderm.
- Fish oil supplement helps the body repair the skin barrier. It is also highly anti-inflammatory. But remember to choose a reliable brand. Many of the fish oil supplements on the market are contaminated. Brands I love that are also third-party tested: Nordic Naturals, Natural Factors Pharmaceutical Grade Fish Oil, and InnovixLab.
- Probiotics that I've tried and quite like: Garden of Life Dr Formulated, Seed, and Visbiome (not affiliated in any sense; purchased all products with my own money)
- Garlic powder supplement and oregano oil capsules daily for 1 week for killing the bad bacteria in my gut
- Homemade bone broth for repairing my gut
- Gluten-free
- No refined carbs at all
- No sugar
- No dairy except kefir
- Lots of greens with some meat each meal
- Berries everyday (there is a study that revealed a correlation between low fruit intake and sebderm in women). Plus, berries are anti-inflammatory
- Avoid using vegetable oil in cooking. Opt for more heat-stable oils that are also low in omega-6s, e.g. extra virgin olive oil, avocado oil, ghee, and butter.
- To sum up, the key is to incorporate as much anti-inflammatory food as possible. Some further examples are turmeric and ginger.
- What I usually eat: https://imgur.com/a/nr1JKne
Summary of helpful resources/research:
- Simple Skincare Science website
- Sezia Website
- Dandruff Deconstructed Website
- Dr. Donovan's blog (He has recently published quite a number of articles on sebderm)
- Ceramide insufficiency in sebderm patients ( https://www.jaad.org/article/S0190-9622(07)01771-9/fulltext#relatedArticles) (https://pubmed.ncbi.nlm.nih.gov/12115025/)
- Niacinamide increases ceramide production (http://fagron.lookhere-dev.co.za/wp-content/uploads/2015/07/Atopic-Dermatitis_Nicotinamide-Tanno-O-2000-BJD.pdf)
- Caprylic and Polygalacturonic Acid Combinations for Eradication of Microbial Organisms Embedded in Biofilm (https://www.frontiersin.org/articles/10.3389/fmicb.2017.01999/full)
- Topical nicotinamide [i.e. niacinamide] for seborrheic dermatitis: an open randomized study (https://core.ac.uk/download/pdf/55117499.pdf)
- Skin moisturizing effects of panthenol-based formulations (https://pubmed.ncbi.nlm.nih.gov/21982351/)
Finally, I want to say that there is still hope. Don't give up. I will pray for everyone in this community to regain their health soon!
Edit: I will continue to edit this and add on to it based on my ongoing research and trial and error. And also to add the things that I forgot to mentionEdit: Added some before and after pics and meal idea pics.
Feel free to message me if you have any questions
Edit on 19 Jan 2022: Now my scalp is free from dandruff with very mild redness, itch is very neglectable like only very mild itch every 5-6 days, and I'm shedding an average of 70 strands of hair daily, which is within the normal range of 50-100 hairs daily as advised by most dermatologists. This is my latest weekly routine (I shampoo four times a week): Neutrogena T/Sal Shampoo --> Philip Kingsley Shampoo for Flaky Scalp (start with as little shampoo as possible because it lathers very well; too much lather can be irritating to the scalp) --> Phillip Adam Apple Cider Vinegar Shampoo (Fragrance Free) --> Ciclopirox 1.5% Shampoo (available by prescription only; alternatives are ketoconazole shampoo and selenium sulfide). Each time after shampooing, I apply the DIY hydrating scalp spray containing 2% panthenol, 2% glycerin, and 4% niacinamide. No longer using the toner as the shampoos I'm using now are very hydrating and gentle.
Edit on 23 Jan 2022: I've just stumbled across some substitutes for this DIY spray from a brand called COSRX. Although they are not hair products, the ingredient lists seem pretty good. This toner (https://www.cosrx.com/collections/toner-mist/products/centella-water-alcohol-free-toner) contains panthenol and sodium hyaluronate, which are both good hydrating ingredients. This one (https://www.cosrx.com/collections/toner-mist/products/bha-blackhead-power-liquid) contains salicylic acid, niacinamide, and panthenol. I'm probably going to try these out soon as I sometimes don't have the time to make the DIY spray. BIG DISCLAIMER: These are not products formulated for the scalp. Use at your own discretion.
Updates on 15 Mar 2022: I'm now using a routine targeted at healing my skin barrier because my scalp is now flake-free but mildly red. Shampooing every other day: ciclopirox shampoo once a week and Bioderma Node A Soothing Shampoo (if you have a really oily scalp, Briogeo Be Gentle Be Kind Matcha Shampoo may be a better alternative) for the rest of the week. Each time after shampooing, I apply some diluted niacinamide serum from The Ordinary because the original 10% may be too irritating. The study that suggested niacinamide as a potential treatment for sebderm used a concentration of 4%. I also added some panthenol powder to the mixture (at a concentration of about 1.5%), which is completely optional. I'm now shedding about 50 hairs daily.
The new HA hydrating serum by The Ordinary did not work for me. I tested it on my hairline, then the sebderm migrated to my hairline while my scalp, luckily, is still clear.
Updates on 12 May 2022: Shampooing every 2-3 days because my scalp is less oily and less itchy. Not using any topical hydrating product because I think my skin has healed so much. Now I'm using ciclopirox shampoo (by prescription only) once a week, and Bioderma Node A Shampoo for the rest of the days
Updates on 7 July 2022: Shampooing every other day; Vichy Dercos Anti-dandruff Shampoo for Oily Hair once a week and Vichy Dercos Anti-dandruff Shampoo for sensitive scalp for the rest of the week; taking anti-inflammatory herbs prescribed by a licensed Traditional Chinese Medicine practitioner (TCM); shedding 40-50 hairs daily; scalp pretty healthy; incorporated more carbs in my diet because realized a low-carb diet makes me shed more hair
Updates on 28 Aug 2022: Shampooing every other day; Vichy Dercos Anti-dandruff Shampoo for Oily Hair every 10 days and Bioderma Node A Soothing Shampoo for the rest of the week; been taking the herbs for almost 2 months now. Noticed my scalp is less oily, zero itch now, no flakes, and redness almost gone. There are some days where I'm shedding only 20-30 hairs daily, which is my pre-sebderm level. But I DON'T recommend visiting a TCM practitioner in western countries. Most of them have no idea what they're doing, and the herbs, if not prescribed properly, can cause damage to the liver and kidney. They are also not well-regulated under the law. My diet is lots of cooked vegetables, some berries, some carbs, and some meat. My TCM doctor told me to avoid seafood (except some fish) and beef.
A Doctor's Approach to Sebderm
Hi!
As the title states, I am a doctor who has been inflicted with this disease for over two years. I have never posted on reddit before. But I felt obliged to because I similar to many of you have found this skin condition to be a real challenge to manage. It is incredibly disappointing to find so little evidenced based research on this topic.
I have had dandruff since my teens but have been able to manage it with head and shoulders. About 2 years ago, I noticed a rash developing on my nasolabial fold but didn't think too much of it. I was to consumed with my work and didn't really pay attention.
Fast forward to this year and the rash progressed to my forehead and was far more noticeable. I self diagnosed myself with sebderm and followed the NICE guidelines (link below)
Scenario: Seborrhoeic dermatitis - face and body | Management | Seborrhoeic dermatitis | CKS | NICE
I used ketoconazole and hydrocortisone to little effect for around 4 weeks. At this point, I decided to get a private dermatologists opinion on the rash. They concurred that it was indeed sebderm and prescribed additional ketoconazole and a tacrolimus ointment.
The tacrolimus cream was very effective. The rash after 2 weeks was barely noticeable. After a 6 week course however it gradually started to return. I decided to use the tacrolimus cream twice a week for maintenance. But about two months ago I decided that I didn't want to become dependent on it. I think many patients share the same stance.
These last three months I have tried a range of products. I attempted using salicylic acid, sebclair cream, zinc pyrithione and miconazole. Tried spending an hour or so outside in the sun (30C). I even tried using manuka honey as many have suggested. Not all at once of course. Nothing worked despite giving each treatment option a decent length of time.
3 days ago, I got myself a bottle of MCT. I would say that for me, the results are comparable to using the tacrolimus cream. I hope that it continues to work in the long run. I use nothing else but a cetaphil moisturizer.
As many of you know, there is a very limited understanding of this disease. I find it mind-boggling that certain treatment options are excluded, because there is no evidence for their efficacy when nobody's actually bothered to hold a trial.
Does diet play a role? Dermatologists don't seem to think so. Based on what?
I intended to post this, just to share my frustration with the community. I don't intend to provide any medical advice from this post.
How to beat Seb Derm, with cited evidence!
Copy and pasted from a comment that I made to a post that was asking for help with her Seb Derm in r/skincareaddiction.
I used to have Seb Derm. It flares up for me during sudden change in weather/temperature, or after showers, or when I'm stressed or sudden change in mood, its really itchy, especially at night, and moisturisers don't really seem to moisturise those affected areas. I've done lots of research regarding Seb Derm, so I'm going to tell you how I beat it, with cited evidence! I've been clear of Seb Derm for almost a year now. Seb Derm happens because there is an active build up of fungus on your face, AKA malassezia. They feed on the yeast on your skin, and the products that you use on those areas/face.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923939/(Not all products tho, ill get to it in a bit).
In order for us to get rid of Seb Derm, you'll have to deprive the Malassezia of their food, whilst also actively trying to kill them. In order for you to do that, you'll need to use products that contain ingredients that do NOT feed malassezia, whilst also using an anti-fungal product to kill existing malassezia. Malassezia feed on certain ingredients, and they usually include majority of oils, and other esters. Please read this link, https://simpleskincarescience.com/pityrosporum-folliculitis-treatment-malassezia-cure/, it'll help you understand, it also provides product suggestions that do not contain ingredients that will feed malassezia.
Having a complete routine that contains no ingredients that will feed malassezia is the first step. You can also use this website https://www.sezia.co/ and copy and paste the ingredients of your products to see if it contains any ingredients that will feed it.
The next step is to find a product with anti-fungal properties to continously eliminate the fungus in those areas of your face. HOWEVER, in order for that product to work, we need to eliminate the biofilm that's been created by the fungus on your face. Have you noticed that the Seb Derm areas on your face is always flakey, slightly raised above your normal skin under certain light, dry, and the texture feels different from your non affected areas of your face. Thats because there is a biofilm on those areas. That is why many people that use anti-fungal products, claim they dont work, because the biofilm prevents the product from actually penetrating into your skin. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3795934/
This website goes a bit more in depth to what biofilms are, https://www.dandruffdeconstructed.com/biofilms-seborrheic-dermatitis/, and the many other methods you can try to disrupt the biofilm.
So in order to destroy the biofilm, and how i personally destroyed it, and many others at /r/SebDerm, we use white vinegar, or rather, acetic acid. White vinegar from your local grocery store contains 4-5% acetic acid with the remaining percentage as water. White vinegar's pH level is ~2.4-2.5 which is really acidic, and not good for sensitive skin. HOWEVER, acetic acid can successfully destroy the biofilm if its pH level is below ~4.3, which is ideal for skin. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4486441/, https://www.nature.com/articles/s41598-017-05178-3. This means we can dilute white vinegar with water into a solution that has appropriate pH levels for skin, whilst also killing the biofilm. Using a cotton pad, apply that solution to your Seb Derm areas on your face for NO MORE than 30-60 seconds, rinsing immediately after in the shower. Doing this once a day, and within a week you'll definitely start seeing results. Once you have determined that there is no more biofilm, where its symptoms that I stated earlier: slightly raised skin, different texturally, flakey, have all subsided, you'll find that your antifungal product will be way more effective, and you can slow down, or stop your vinegar treatment. The White Vinegar method can really make your face red at first, but will subside as you proceed. Make sure to pack on heaps of moisture from your fungal safe moisturiser.
Now the number one anti-fungal product that I can recommend, and also one of this subreddit's favourite skincare ingredient to use too is... Azelaic Acid. Azelaic acid is anti-fungal, anti-bacterial, anti-keratinizing, and anti-inflammatory, which are all properties that are extremely useful for Seb Derm patients. https://www.ncbi.nlm.nih.gov/pubmed/19213227. It is typically a product for rosacea, but is also found useful for acne, hyper-pigmentation etc. making this ingredient an all-star. There was also a study conducted where patients were instructed to apply 15% azelaic acid to their Seb Derm areas once daily, http://trialfinder.bayerscheringpharma.de/html/pdf/1401201_Study_Synopsis_CTP.pdf. The results stated that it remained effective for ONLY 2 weeks, any anytime after that was minimal improvement. So why would I recommend azelaic acid for your Seb Derm if the result from the study shows that it is only effective for the first 2 weeks? That's because the study didn't take into consideration the biofilm that is present in Seb Derm. There have been many users online that stated that they've tried an anti-fungal product, only for it to work for a couple of weeks and then it didn't. Many users responded saying it could be that the bacteria is being more resistant, AKA anti-bacterial resistance, towards the product that they are using. I don't think that is the case, going back to my other point, its because the bacteria, or malassezia is being protected from their own created biofilm. The study also didn't state if the patients were using a fungal safe routine.
EDIT: According to these 2 studies that I linked earlier, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4486441/, https://www.nature.com/articles/s41598-017-05178-3, they used 2 solutions that consisted of 0.5% and 1% acetic acid. Both were able to completely eradicate the biofilm and fungus 100%. Assuming that your standard white vinegar bottle is 4% acetic acid and 96% water, which mine is, you'll want to dilute the vinegar so that the acetic acid concentration sits between 0.5% and 1%. Which means for every 100 mL of vinegar, you'll want to add a minimum of 300 mL of water making it a 400 mL solution with 1% acetic acid, OR add up to a maximum of 700 mL of water making it a 800 mL solution with 0.5% acetic acid. This golden ratio would be between 1:3 and 1:7, Vinegar:Water. This makes the pH range of the solution ~2.8 - 3.5 which is far better for your skin. If you don't think thats a big jump from vinegar's base pH of 2.4, remember that a pH of 2 is 10x more acidic than a pH of 3, and 100x more acidic than a pH of 4.
TLDR: Use products that don't feed Malassezia, aka, a fungal-safe routine.
Destroy the biofilm present on your Seb Derm areas.
Use anti-fungal product (I recommend Azelaic Acid) to destroy remaining Malassezia present on Seb Derm areas.
Academic here, popping in to share some new research on SebDerm and hopefully directions for treatment
I am seeing a lot of posts here about treatment recommendations and products but frankly missing the mark. I want to show some recent studies (2-3 years) that are changing the way we approach the treatment of SebDerm.
First thing first, your skin is the largest organ of your body. (Yes it is an organ, like your kidney, liver and lungs). On that organ lives microorganisms much like the microbiome of your stomach.
Sebhorreic Dermatitis (SD) is a type of chronic inflammatory dermatitis that effects at least 50 million Americans, and $300 million are spent on Over-the-Counter products every year (aka you're not alone and this sub should be millions more strong!).
For the past century, it is thought that Malassezia yeast colonization of the skin surface in lipid-rich areas leads to an inflammatory response due to the secretion of free-fatty-acids (FFA) and lipid peroxides on the skin. Your immune system generates selected cytokines (e.g., interleukins (IL): IL-1, IL-2, L-4, IL-8, IL-10, IL-12, TNC-alpha) that stimulates keratinocyte proliferation and differentiation. Soon, the skin barrier is disrupted and shows in visible forms like erythema, pruritus, and scaling. Of the 21 species of Malassezia, Malassezia restricta (M. restricta) and Malassezia globosa (M. globosa), M. arunalkei, M. sympodialis are associated with the majority of SDs.
The type of Malassezia you get is different by geographic location and age, but all that is important here is that the agreed model of pathway for the development of SebDerm is (1) skin instability - > (2) skin becomes less selective for microbial growth -> (3) dysbiosis (worsens abnormal immune response) -> (4) skin barrier disruption -> (5) symptoms. The condition is chronic because steps 1, 2, 3 are cyclical. This means that if we don't address the root cause, Malassezia will continue to colonize and recolonize areas with lipid-secretion (i.e., your sebaceous glands, which is most abundant on your face and scalp).
In short, SebDerm is a chronic inflammation of your biggest organ, and the inflammation is caused by your immune system oversecreting cytokines in a response to the "poops" of Malassezia, who happens to love eating fat. However, nobody in the scientific community has ever confidently said "Malassezia yeasts cause Seb Derm and if we eliminate Malassezia we can cure Seb Derm", because Malassezia has lived with us harmoniously for as long as humans exist. Instead, scientific literature conservatively say "treatment should manage to reduce the colonization of Malassezia, then apply medications that regulate sebaceous gland activity, and restore epidermal barrier function". That is because the etiopathogenesis (the cause and development of a disease of abnormal condition) has never been established [Wilkramanayak et al, 2019] (https://europepmc.org/article/med/31310695)
In recent years, we find an old friend - Staphylococcus aureus (S. aureus), more specifically, Methicillin-Resistant Staphylococcus aureus (MRSA) - a difficult to treat Gram-positive bacteria that causes severe infections in humans - as one of the precursors to Malassezia overgrowth.
Disclaimer: S. aureus lives in 20-30% of all humans, in healthy humans it doesn't cause harm, and it contributes to things like pimples and cellulitis but nothing of major concern. However, once a person is sick or immunicompromised, those with S. aureus find it harder to fight off infections, have more chances of dying due to pneumonia, toxic shock syndrome, endocarditis, etc. S. Aureus of any kind is something you don't want, but it's everywhere and gets passed around by skin-contact. This is why in infection management, hospital scrubs are not supposed to be worn outside of the hospital to prevent the spread of hospital-acquired MRSA among the general population.
What is the significance of this exciting finding? This means that we may have found the root cause to SebDerm. Removing S. aureus (where it shouldn't be) may prevent the destabilization of skin barriers and reduce colonization of Malassezia, thereby reducing the skin's inflammation (aka SebDerm).
There are many in-vivo, ex-vivo, and prospective observational studies registered and underway to examine the effects of S. aureus on all sorts of dermatitis, including Seb Derm. I mean, how could we have overlooked this important and nasty bacteria which we have known all along to cause all sorts of skin problems? Read last paragraph.
What are the implications for treatment of SD in the future? First, corticosteroids will be off the table. (Remember just 100 years ago, what we consider were absurd practices like using cocaine to treat alcoholism, arsenic for syphilis, and smoking for asthma were common place). Second, physicians may resort to examining the skin microbiome, swabbing the skin to detect S. aureus, MRSA, and Malassezia to determine treatment plans. Third, a prescription of antifungal and antibacterial will be used while focusing on restoring epidermal homeostasis.
What are some current treatment that works? Antibiotics like fluroquinolone antibiotics (e.g., ciproflaxocin), mitronidazole, cefalexin, etc, can kill off S. aureus. Antifungals like ketoconazole (topical), itraconazole (oral), bifonazole (oral), allylamines (terbinafine), the benzylamines (butenafine), and the hydroxypyridones (ciclopirox) have also shown to be affective. More studies are now testing cosmetics containing a combination of ingredients to inhibit S. aureus growth: combination 1: hydroxyacetophenone,phenylpropanol, propanediol, caprylyl glycol, tocopherol), Combination 2: hydroxyacetophenone,phenylpropanol, propanediol, caprylyl glycol, tocopherol, and tetrasodium glutamate diacetate. Pinto et al, 2022
To all the people who got treated with corticosteroids, your outdated physicians are performing outdated practices. By outdated I mean that if the physician graduated from medical school even just 5 years ago, he/she would not have been equipt with the information dermatologists in training would have now. That is because the research into human microbiome and its effects on skin diseases were restricted by limitations in computational capacities in genetic sequencing and culture-dependent methods. In the last 5 years, non-culture-based studies allow us to study bacteria that were previously culture- dependently (on a plate), and more sophisticated computational techniques allow us to combine and mix-and-match samples to observe the pathogenesis of the microbiome and diseases in a complexity like never before, reducing the effect of heterogeneity of individuals.
TL;DR: The etiopathogenesis of SebDerm has never been formally established, the new working hypothesis in the last 4 years is that Staphylococcus Aureus (and more specifically, MRSA) is the culprit, leading to skin barrier dysfunction and opportunistic colonization of Malassezia yeasts which induces inflammatory responses clinically representing as SD. Treatment guidelines may soon change to exclude corticosteroids and focus on antifungal and antibiotics to rid of S. Aureus; many labs have taken to explore cosmetics and applications of a combinant of ingredients to inhibit bacterial growth after the restoration of skin barrier and modulation of the sebaceous gland to prevent recurrence. Good luck out there!
References:
Tamer, F., Yuksel, M. E., Sarifakioglu, E., & Karabag, Y. (2018). Staphylococcus aureus is the most common bacterial agent of the skin flora of patients with seborrheic dermatitis. Dermatology practical & conceptual, 8(2), 80.
Wikramanayake, T. C., Borda, L. J., Miteva, M., & Paus, R. (2019). Seborrheic dermatitis—looking beyond Malassezia. Experimental dermatology, 28(9), 991-1001.
Adalsteinsson, J. A., Kaushik, S., Muzumdar, S., Guttman‐Yassky, E., & Ungar, J. (2020). An update on the microbiology, immunology and genetics of seborrheic dermatitis. Experimental dermatology, 29(5), 481-489. Flowers, L., & Grice, E. A. (2020). The skin microbiota: balancing risk and reward. Cell host & microbe, 28(2), 190-200.
Lin, Q., Panchamukhi, A., Li, P., Shan, W., Zhou, H., Hou, L., & Chen, W. (2021). Malassezia and Staphylococcus dominate scalp microbiome for seborrheic dermatitis. Bioprocess and Biosystems Engineering, 44(5), 965-975.
Pinto, D., Ciardiello, T., Franzoni, M., Pasini, F., Giuliani, G., & Rinaldi, F. (2021). Effect of commonly used cosmetic preservatives on skin resident microflora dynamics. Scientific Reports, 11(1), 1-7.