Aromatase inhibitor‐induced skin adverse reactions: exemestane‐related cutaneous vasculitis

Background  Three aromatase inhibitors, namely anastrozole, letrozole and exemestane, which reduce circulating oestrogen, are used to treat breast cancer patients; the therapeutic use of such aromatase inhibitors is quickly increasing. Objective  We intended (i) to review aromatase inhibitor‐induced cutaneous adverse effects and (ii) to describe a recently observed case of cutaneous vasculitis triggered by exemestane. Patients/methods  The so‐far reported literature cases of aromatase inhibitor‐induced cutaneous adverse effects were analysed retrospectively. Especially, the clinical case of exemestane‐induced cutaneous vasculitis herein reported is unique, because such an observation has not yet been published in the literature. Results  Merely 12 cases of cutaneous adverse reactions induced by aromatase inhibitors, namely erythema nodosum (6), subacute cutaneous lupus erythematosus (1), cutaneous rashes (2), vasculitis (3, including the one described in this study), are reported in the literature. In fact, in the present case, cutaneous vasculitis was strictly related to exemestane. Conclusion  As aromatase inhibitors (e.g. exemestane) are increasingly incorporated into the treatment strategy of breast cancer patients, it is important to recognize possible cutaneous adverse effects. Specifically, with regard to cutaneous vasculitis, some patients might progress to severe vasculitis manifestations if the offending drug (e.g. exemestane) is not quickly stopped.