Racial disparities in skin tone representation of dermatomyositis rashes: a systematic review

Objective This systemic review assesses skin tone representation in images of DM rashes in medical education literature. Methods A review was performed of 59 dermatology, 11 neurology, 10 neuromuscular, 7 rheumatology and 6 internal medicine textbooks published between 2011 and 2021 and 3 online image databases (UpToDate, VisualDx and DermNet NZ) that were available through an online medical school library. After extracting images, images with poor lighting or unclear rashes were removed. Authors graded skin tone independently on the Massey and Martin Skin Colour Scale (MMSCS) from 1 (very light) to 10 (very dark). The median score was taken for a final score, grouped within MMSCS 1-2, 3-4, 5-7 or 8-10. Inter-rater reliability was assessed using Kendall's coefficient of concordance (W). Results Six hundred and twenty-one images were extracted after reviewing 93 textbooks and 3 online databases. Of the 561 images analysed, 73.1% of images represented MMSCS 1-2, followed by 3-4 (13.4%), 5-7 (11.8%) and 8-10 (1.8%). Inter-rater reliability was high (W = 0.835). Of the images in MMSCS 5-10, 59.2% were in online databases and 80.6% of textbook images were in dermatology books. Conclusions Patients with lighter skin tones were represented in a higher number of DM-related educational materials compared with patients with darker skin tones. Our findings add to current research implicating that darker skin tones are under-represented in cutaneous educational materials, specifically for DM. This leads to the inability to properly characterize skin involvement in DM and may lead to inappropriate exclusion from clinical trials due to erroneous skin scoring.