Ivermectin, a new topical treatment for the management of papulopustular lesions of rosacea.

Ivermectin is a substance derived from avermectin, a macrocyclic organic compound with insecticidal properties isolated from the fermentation of the bacterium Streptomyces avermitilis. The value of ivermectin in the dermatological field lies in its ability to reduce redness and papules and pustules, characteristic symptoms of papulopustular rosacea. Moreover, thanks to its anti-parasitic action, ivermectin also works by suppressing the activity of the mites Demodex Folliculum, whose proliferation is believed to be involved in the development of papulopustular rosacea. Generally, this antibiotic contributes to improving the quality of life of patients suffering from rosacea by reducing the daily embarrassment caused by its various symptoms.

By reducing skin inflammation, ivermectin alleviates erythema and decreases the number of papulopustular lesions.

From a mechanistic perspective, ivermectin works by binding to the glutamate-dependent channels of parasites, including those of Demodex Folliculum. This causes hyperpolarisation of the cells by increasing the membrane permeability to chloride ions, leading to the death of the microorganisms. Furthermore, ivermectin has anti-inflammatory properties at the site of skin lesions. Indeed, it is capable of inhibiting the production of certain pro-inflammatory cytokines by immune cells, such as interleukins 1 and 6 (IL-1 and IL-6) induced by lipopolysaccharide (LPS), thus reducing the redness, papules and pustules characteristic of papulopustular rosacea.

The efficacy of ivermectin in combating papulopustular rosacea was assessed in two recent identical clinical studies conducted in parallel. Patients were given a formulation containing 1% ivermectin or the same cream without ivermectin. After 12 weeks of daily application, an improvement was observed in 38.4% and 40.1% of patients in the "ivermectin" groups compared to 11.6% and 18.8% in the "placebo" groups. Furthermore, reductions in the numbers of inflammatory lesions of 76.0% and 75.0% for the "ivermectin" groups versus 50.0% for the "placebo" groups were recorded. Ivermectin thus appears to be a promising drug for combating papulopustular rosacea.

Its effectiveness has also been compared to that of metronidazole, commonly used to treat papulopustular rosacea. For this, 962 patients were divided into two groups and received either a 1% ivermectin cream or a 0.75% metronidazole cream. After 16 weeks of daily application, a significant improvement was observed in 84.9% of the patients in the "ivermectin" group, compared to 75.4% of those in the "metronidazole" group. Ivermectin thus appears to be an interesting alternative to metronidazole in the case of papulopustular rosacea.