Halo nevi are moles that develop a white halo around them. This loss of pigmentation is due to the patient’s own immune system attacking the melanocytes (pigment producing cells) around and ultimately within the mole. It is not clear why this phenomenon occurs but it is thought that occasionally it may be that the immune system is fighting an unrecognised melanoma elsewhere on the body and as a side effect it also attacks some innocent melanocytes as well, producing the halo phenomenon. So how concerned should we be about the risk of a melanoma in a patient presenting with a halo nevus? A recent study looked into this by retrospectively looking at 879 adults who had been diagnosed with at least one halo nevus and seeing how many of these patients were subsequently diagnosed with a melanoma. The conclusion was that having a halo nevus afforded a similar risk of melanoma as having multiple atypical nevi or having a family history of melanoma. This risk was about 1% in the year following diagnosis. The recommendation the authors give is that a diagnosis of a halo nevus should initiate an annual complete skin cancer screening exam. So look out for changes in your moles including a heavenly halo!
Association Between Halo Nevi and Melanoma in Adults: A Multi-Center Retrospective Case Series
J Am Acad Dermatol 2020 Aug 18;[EPub Ahead of Print], D Haynes, JL Strunck, J Said, I Tam, A Varedi, CA Topham, B Olamiju, BM Wei, MK Erickson, LL Wang, A Tan, R Stoner, RI Hartman, E Lilly, D Grossman, JA Curtis, JS Westerdahl, JS Leventhal, JN Choi, EY Chu, ME Ming, JA Stein, TN Liebman, E Berry, TM Greiling