ALLERGIC REACTIONS TO TATTOO PIGMENT AFTER LASER TREATMENT

BACKGROUND. Cutaneous allergic reactions to pigments found in tattoos are nor infrequent. Cinnabar (mercuric sulfide) is the most common cau se of allergic reactions in tattoos and is probably related to a cell- mediated (delayed) hypersensitivity reaction. OBJECTIVE. The purpose o f these case presentations is to describe a previously unreported comp lication of tattoo removal with two Q-switched lasers. RESULTS. Two pa tients without prior histories of skin disease experienced localized a s well as widespread allergic reactions after treatment of their tatto os with two and-switched lasers. CONCLUSION. The Q-switched ruby and n eodymium:yttrium-aluminum-garnet lasers target intracellular tattoo pi gment, causing rapid thermal expansion that fragments pigment-containi ng cells and causes the pigment to become extracellular. This extracel lular pigment is then recognized by the immune system as foreign.