WISE1 versus MAD_wise1 diagram for RSGs in NGC 55 and NGC 300. The color bar indicates the luminosity for each RSG, and the gray dots indicate cases where a luminosity was not obtained. Black stars indicate eight RSGs that were reported as variable in optical surveys. Open circles indicate dusty RSGs. The dashed black curve indicates the median MAD for non-dusty RSGs. Four RSGs with both optical variability and a high MAD value relative to their WISE1 magnitude are labeled.