Rosacea and Tiny Mites

Mites scare me.

When I was an undergrad, working on fruit flies (I would sit in a coldroom, which was essentially a big refrigerator, injecting fruit fly eggs with a tiny glass needle I blew myself, making some of the very early transgenic fruit flies), mite infestations would occasionally sweep through the lab, killing hundreds of thousands of fruit flies. Some of the flies represented years of work by students and postdocs.

Which brings us to rosacea. Rosacea is a devastating disease. It turns the face bright red, often with pustules and bumps all over the face. Like psoriasis, many people who develop severe cases become a recluse, refusing to socialize. The psychological effects can be terrible

Rosacea has been the bane of many practitioners, because while it can respond to therapy, it sometimes is very difficult to treat.  This is why I was surprised and pleased when I learned there was a new FDA-approved treatment.

I was shocked to find out, however, that it was ivermectin. Ivermectin is an anti-parasitide. I am familiar with the drug since I work in veterinary medicine. That was one of the last medicines I would have expected to be used for rosacea.

But here is the reason it seems to work: it seems that a strong correlation has been established between the amount of demodex mites and rosacea. What are demodex mites? They are tiny (less than half a milimeter in length) insects that live on our skin, mostly inside our fair follicles. About 1/3 to 1/2 of us have these six-legged critters living on our skin. They look like this:

Yes, you heard that right. Tiny little insects. On our face. Living happily.

Normally, the mites don’t seem to cause much trouble. But in people with rosacea, there are up to ten times as many mites on their faces. It seems that when you kill the mites, the disease gets better.

But that’s not all. It seems that it may not be the mites themselves, but rather tiny bacteria that live on the mites, called bacillus oleronius, may be responsible. The mite may just move those bacteria around.

What makes this even more interesting is that there might be an association between the mites and some types of acne. It has long been a mystery why certain dermatological conditions, including acne and psoriasis respond to antibiotics. Maybe it’s time to take another look at the facial microbiome,