Allergic Reactions to Tattoo Pigment after Laser Treatment

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.