In recent years new, obscure or poorly known dermatological disorders have been described and better defined, with emphasis on clinical, histopathological and etiopathogenetic features. Familiarity with these new, emerging or revisited clinical entities is fundamental, and recognizing them with their differential diagnosis has important implications in clinical practice for better patient management. This book offers an in-depth discussion of the clinical and pathologic features of newly described or less well-known and revisited cutaneous disorders. It provides clinical findings, as well as the histologic, immunologic, and molecular features of these diseases in addition to therapeutic notes. The first section of the book covers cutaneous diseases that lack any systemic implications, such as circumscribed palmoplantar hypokeratosis, necrotizing infundibular crystalline folliculitis, and dermal hyperneury, amongst others.