FAQ - Malassezia

Here are easily understandable answers to the most frequently asked questions. More detailed answers can be found on the Details! page.


What are Malassezia?

Malassezia are fungal colonizers of humans and animals (Theelen et al 2018). They are best known as the cause of dandruff, a benign condition which affects about half of the adult population. They used to be called Pityrosporum, and many people still use the old name.

Can Malassezia on our skin make us sick?

Malassezia typically colonize our skin without causing any symptoms. In some people, Malassezia can cause seborrheic dermatitis, pityriasis versicolor and folliculitis. None of these are life threatening, and can be treated with fungicides such as ketoconazole shampoo.

Do we have Malassezia inside our bodies?

Until very recently, the textbook answer was: “No, Malassezia only colonize the skin of mammals”. In the 1980s, reports emerged of Malassezia causing acute infections inside the body, but this usually occurred in immunocompromised patients, so it was considered a rare exception (Shek et al 1989). We now know the textbook answer was flat out wrong: many research groups report finding Malassezia in the bodies of healthy adults (Dupuy et al 2014; Cleland et al 2014; Hallen-Adams et al 2015; Liguori et al 2016; Boix-Amoros et al 2017; Alonso et al 2018; Abusleme et al 2018; and many more), as well as in non-mammalian species (Amend 2014). So the answer is: “Yes, Malassezia are found in many organs of healthy humans.”

OK, Malassezia reach our internal organs, so what?

We know with certainty that Malassezia cause inflammatory skin conditions such as seborrheic dermatitis (Gupta et al 2004). Is it reasonable to assume that Malassezia never cause inflammation when inside the body? No! So what would seborrheic dermatitis inside the brain look like? Maybe it’s Parkinson’s disease. And so on, for each organ where Malassezia are found.

Which Malassezia species are found within our bodies?

Currently, the main species found within humans are Malassezia restricta and Malassezia globosa. There may be additional Malassezia species which often reach our internal organs, it’s too early to know for sure.

How can I “catch” Malassezia?

Shortly after birth, Malassezia have already colonized our skin for life (Nagata et al 2012), so we all “catch” Malassezia at a very young age. It seems Malassezia usually wait until puberty or early adulthood to permanently colonize our guts and genitals. This coincides with, and probably explains, the onset of chronic idiopathic inflammation of these organs in many people. The prevalence of Malassezia in other internal organs is not yet clear.

How can I eliminate Malassezia from my body?

Once an organ is colonized with Malassezia, our immune system doesn't seem able to clear them on its own. Antifungal shampoos can be used to reduce Malassezia populations on the scalp, and this cures dandruff. However, if this shampoo is no longer used, Malassezia and dandruff return. The efficacy of antifungal drugs on Malassezia inside the body has not been studied, so we don't know how well each drug works. A Crohn’s study suggests oral itraconazole may be effective against Malassezia in the gut (Samuel et al 2010).


FAQ - The Malassezia Project


What’s The Malassezia Project?

Until 2018, I was not sure which fungal genus was involved in prostate cancer, I only knew that our bodies produce the antimicrobial protein PSP94 to fight this fungus and protect us from this cancer. So from 2012 to 2017, I called it “The PSP94 Project”. During this period, my main goal was to determine which fungus was the culprit in prostate cancer. This phase is now complete. The next phase consists of funding university research groups to run clinical trials to determine which antifungal drugs can clear Malassezia from the body, and thus cure or prevent Crohn’s disease, ankylosing spondylitis, prostate cancer, benign prostatic hyperplasia, etc.

Who’s running this project?

My name is Martin Laurence. I’m a bioinformatician working for a small lab in Montreal, Canada. Previously, I designed computer chips for a living. Many academic researchers have directly contributed to this project in their respective fields (my coauthors), and many more have helped out without being credited. Patients have also helped: after reading my articles on Pubmed, they’ve pointed out important articles which I had not seen. I’m forever grateful to these folks for their encouragement, enthusiasm and generosity.

Are you credible?

I’d like to think so! I don’t have a graduate degree in biology, I am not affiliated with a university and my PCR machine is made of wood. Despite this, I’ve published peer reviewed articles with established researchers at Johns Hopkins, Yale, Washington University, Oregon Health & Science University and Universidad Complutense de Madrid. Imagine how high that bar was!

How are you going to make money with this?

I’m not. I’ve spent much of my retirement savings supporting basic research for this project already.

Why do you care about this then?

I know folks who have had prostate cancer, Crohn’s disease or spondyloarthritis. They’ve suffered a great deal. There are millions more like them, suffering right now. If tables were turned, would I want an obscure Canadian to do all he can to cure me? Absolutely! Enough said.