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  • Writer's pictureDr. Leslie Baumann

Are your patients using an OTC Horse Dewormer to Kill Mites That May Cause Rosacea?

Updated: Mar 25, 2020

The skin’s microbiome is made up of a wide variety of living organisms – many of which are harmless or even beneficial. However, when there is an imbalance of microorganisms living on the skin, problems such as acne and maybe even rosacea can occur. For years, researchers have linked larger numbers of Demodex mites with rosacea. Although not all patients with rosacea have Demodex mites, prescription medications such as Soolantra (ivermectin) have been shown to improve rosacea in many patients.

Lately, there has been talk on the dermatology chat groups about patients buying a 1.87% ivermectin paste on Amazon that is used for horses. It is called Duramectin. I have not tried it in my patients, but it has been reported to reduce Demodex mites. Have any of you seen this or had patients use it? Please share your experience with us.

What Are Demodex Mites?

Demodex mites are microscopic organisms that are naturally present on human skin, regardless of skin type. However, rosacea patients tend to have a higher number of these mites living on the skin, which has lead scientists to believe that these mites may contribute to rosacea symptoms. A 2018 paper published in the British Journal of Dermatology sheds new light on how these mites may affect the skin.

According to the study, Demodex mites secret bioactive molecules that “turn on” what are called toll-like receptors (TLRs) in the skin. Specifically, Demodex seems to affect TLR-2, which has also been indicated in acne. Researchers found that only high numbers of Demodex had this effect on TLR-2 in the skin, leading to inflammation that may cause or trigger rosacea. Demodex mites seem to play a role in all subtypes of rosacea.

demodex mites

Demodex Mite image – Used with permission from shutterstock

What Are Toll-Like Receptors?

Toll-like receptors are able to recognize certain harmful proteins, lipids, and nucleic acids. When TLRs detect harmful substances, they “turn on” your body’s inflammatory response system as a defense mechanism. When treating certain diseases like viral infections and skin cancer, the inflammatory response triggered by TLRs is very important. However, when managing inflammatory skin diseases like rosacea and acne, TLR expression can worsen symptoms. Therefore, TLRs that are activated by large colonies of Demodex on the skin is believed to contribute to rosacea.

toll like receptor 4

This is an image of a Toll Like 4 receptor used with permission from Shutterstock. (Toll like 2 receptors look very similar).

How to Get Rid of Demodex Mites

Removing excess amounts of Demodex mites from the skin can help to better manage rosacea symptoms. Soolantra (1% ivermectin) is a topical prescription cream that is used to kill Demodex mites and may also have anti-inflammatory properties. The active ingredient, ivermectin, is what is used to get rid of parasites in pets. I don’t recommend to my patients to self-medicate with medications formulated for animals, as the dosage and concentration can widely vary.  

Strange Non-prescription Anti-Demodex Alternatives

Prescription ivermectin is very expensive (Soolantra can be as high as $500) and patients and physicians are often looking for cheaper solutions. Some patients have been telling me that they have tried a Duramectin horse paste that they found online. It is very thick and difficult to spread. If your patients choose to use this, it is important to remember that it is 1.8% rather than the FDA approved 1% dose, so once a day application is best. Also, Duramectin has propylene glycol in it that can irritate sensitive skin types – can you believe that Soolantra also has propylene glycol in it?!

Duramectin has not seemed to cause any serious adverse events from the little bit of information that I have heard. Topical permethrin works for Demodex mites, but is very irritating to rosacea-prone skin. Skinmedicinals makes a “Rosacea Triple Cream” that I have heard good things about but have not used. Some dermatologists use an oral ivermectin of 1mg for every 10 pounds. However, this is an off-label use. I personally prescribe Soolantra for my patients and combine it with other prescription medications such as Rhofade in addition to an anti inflammatory skin care regimen and diet.

In Summary

We’re still learning more about what causes rosacea and developing new treatments for it. There is a growing body of evidence to suggest that large numbers of Demodex mites on the skin may contribute to rosacea symptoms by activating toll-like receptor 2 and causing inflammation. Fortunately, there are prescription treatments like Soolantra that can help to control Demodex populations and reduce rosacea flares. But lately they have been very expensive. Patients are looking for more affordable alternatives. Please share your off-label uses for rosacea with us so we can all learn from each other.

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