Drug‐induced hypersensitivity syndrome (DiHS) is a severe drug eruption that can induce reactivation of herpesviruses such as human herpesvirus 6, resulting in symptom flare‐up and organ damage. DiHS is known as drug reaction with eosinophilia and systemic symptoms (DRESS) in Europe. We report three cases of DiHS that could have been triggered by mRNA‐based coronavirus disease 2019 (COVID‐19) vaccines. In these three patients, symptoms of DiHS developed 2–6 days after the first dose of an mRNA‐based COVID‐19 vaccine. Although there have been no reports of DiHS/DRESS induced by mRNA‐based COVID‐19 vaccines in domestic and international journals despite the progress in vaccination worldwide, we speculate that mRNA‐based COVID‐19 vaccines might have triggered the development of DiHS/DRESS in our patients. In the current coronavirus epidemic, it might be important to assess mRNA‐based COVID‐19 vaccination status and date of vaccination when evaluating a patient with DiHS/DRESS.

Spitz nevus (SN) is predominantly distributed throughout the lower extremities, while an acral location is rare. Since SN occasionally resembles the clinicopathological presentation of malignant melanoma (MM), it presents a diagnostic challenge, especially on glabrous skin. Past reports suggest that several genetic aberrations are associated with specific clinicopathological subtypes of melanocytic tumors. Immunohistochemistry can provide a clue to the presence or absence of a molecular aberration typical of Spitz tumors. We describe a case of a plantar SN with genetic analysis, including anaplastic lymphoma kinase (ALK), ROS proto-oncogene 1 (ROS1), BRAF (V600E) protein, and BRCA1-associated protein-1 (BAP1). However, we were not able to detect a characteristic gene aberration. To the best of our knowledge, no genetic aberrations in plantar SN cases have been reported. A comprehensive understanding of tumor genomics is expected to play an essential role in the classification of melanocytic tumors. Further genetic research on plantar SN is required to establish new criteria for distinguishing between SN and MM.