The "rainbow" pattern is a relatively new dermoscopic term that describes a bluish-reddish coloration together with various colors of the rainbow observable mainly through polarized light dermoscopy. Despite several theories, the rainbow pattern has not yet been clearly associated with any particular histological structure. This feature has been described in skin lesions with abundant vascularization such as Kaposi's sarcoma, basal cell carcinoma, scars, squamous cell carcinoma, melanoma, and others. In this paper we conducted a review of the available studies regarding the appearance of the rainbow pattern in different pathologies. Furthermore, we present a detailed description of the physical phenomenon in order to obtain a better understanding of this peculiar dermoscopic feature.