Background: Cutaneous allergic reactions to pigments found in tattoos are not infrequent. Cinnabar (mercuric sulfide) is the most common cause of allergic reactions in tattoos and is probably related to a cell-mediated (delayed) hypersensitivity reaction.
Objective: The purpose of these case presentations is to describe a previously unreported complication of tattoo removal with two Q-switched lasers.
Results: Two patients without prior histories of skin disease experienced localized as well as widespread allergic reactions after treatment of their tattoos with two Q-switched lasers.
Conclusion: The Q-switched ruby and neodymium:yttrium-aluminum-garnet lasers target intracellular tattoo pigment, causing rapid thermal expansion that fragments pigment-containing cells and causes the pigment to become extracellular. This extracellular pigment is then recognized by the immune system as foreign.