I pretty much know where the problem areas are in my body. One of them is the Lymph system, especially on my left side (Entire left side of body).
If you check a good Foot Reflexology chart, the upper left foot where it joins the ankle (The 'hinge' area between instep and ankle) is the reflex area for the left-side Lymph system.
That area began itching like *crazy* after I started supplementing with Lugol's. As the itching abated, left ankle swelling went down. I checked the ankle skin, expecting to see it red/dry. It wasn't, but it sure did itch.
Also in other areas where I know for a fact there are localized problems, I could actually feel the Lugol's working on the boundaries of those areas, and, even internally (Where I couldn't scratch it), the sensation was like an itch/activation.