Tattoo allergy in patients receiving adjuvant radiotherapy for breast cancer.

Tattooing is routinely employed prior to radiotherapy treatment but allergies to tattoos are rare. New information on the incidence of tattoo allergy at St George Hospital is presented with details of two clinical cases. The literature on tattoo allergy has been unable to estimate the incidence of allergic reaction to tattoos because the total number of patients treated is unknown and not all patients were followed up. Our radiation oncology population for the first time has provided a known denominator, but wide confidence intervals prevent an accurate estimate of the incidence. Salient issues about tattoo allergy are highlighted based on a review of the published literature from 1966 to 1998.