As a pathologist who sees tattoo ink in lymph nodes routinely (along with other pigments), it's slightly shocking to me that this got reported as a finding.

There is, however, an interesting suggestion of correlation between certain red pigments, particularly from tattoos made in Asia it seems, that stimulate the immune system to mount a severe epidermolytic reaction. And it can be a delayed reaction. We had one where the dermatologists brought in pictures. It looked like the entire tattoo was being cut out with a cookie cutter, just totally separated from the surrounding skin. Horrible.