My skin troubles started with what I self-diagnosed as a demodex infestation – extremely itchy and inflamed eyelids and eyebrows, which began during a stay at an unexpectedly shabby airbnb – which has seemed to slowly but steadily spread downward. The eyebrow thing started over Memorial Day weekend in 2018; by the end of summer, my whole face felt inflamed; by the end of the year I was diagnosed with rosacea and was starting to have an itchy neck with inflamation in the creases; bumps then appeared on my shoulders and chest, and I was diagnosed with GD based on a biopsy; now it's gone down my arms and is worst in my armpits and inside my elbows. The docs seem to see what's going on in different areas as unrelated – rosacea vs. GD vs. something fungal – but to me the spread of one kind of itchiness or another has seemed very steady, continually downward, so I can't help but feel they're related.

Anyway, I've been using soolantra or ivermectin cream on my face for the rosacea for at least a year and a half, and for many months – probably a year or so – also used it on the back of my neck, hoping it would help with the GD there, but I can't say it did. More recently, my insurance stopped covering soolantra or ivermectin cream, and it's terribly expensive, so I stopped using it on my neck at least a month ago, and my neck does not seem any worse.

I also tried a course of oral ivermectin, which is supposed to kill demodex, going to great lengths to sanitize all my clothes, bedding, hairbrush, etc. – but noticed no improvement at all.

The short answer: I've concluded that, at least for me, ivermectin doesn't help the GD much, even if it helps with the rosacea.