Eruptive melanocytic nevi (EMN) are nevi that appear unexpectedly. The study’s goal was to consolidate all published EMN data in order to identify potential triggering variables and to assess the clinical presentation and progression. Researchers did a comprehensive review of the literature and chose 93 studies that represented 179 EMN patients. Skin and other disorders, immunosuppressive drugs, chemotherapy, or Melanotan, and other reasons, including idiopathic, were all suspected. The clinical symptoms can be broadly classified into two groups: EMN caused by skin disorders were typically few in number, big, and restricted to the location of prior skin disease, but those caused by other sources were most commonly characterized by several little scattered nevi. In general, EMN appears to remain intact when they emerge, however development over several years or fading has also been documented. At least one histologically verified dysplastic nevus was seen in 16% of the patients. There have been five recorded cases of related melanoma. 

They conclude that the clinical manifestations of EMN may differ depending on the triggering cause. They suggest a new EMN subclassification based on clinical distinctions: (1) widespread eruptive nevi (WEN), with numerous little nevi, driven by factors such as medications and internal disorders, and (2) Köbner-like eruptive nevi, frequently with large and rare nevi, related with skin diseases and most commonly localized to the site of past skin disease/trauma. Due to the nature of the data, determining the risk of malignant transformation was impossible.

Reference:https://link.springer.com/article/10.1007/s40257-019-00444-8