Panniculitides represent a heterogeneous group of inflammatory diseases that are traditionally considered one of the most difficult challenge for clinicians and pathologists. They may occur in a variety of dermato/rheumatologic diseases and are of particular relevance for clinicians dealing with such pathologies, including immune-mediated/autoimmune and autoinflammatory disorders. In fact, panniculitides can be the initial sign of presentation of a dermato/rheumatologic disease, thereby providing the physician with important clues to the correct diagnosis. Then, panniculitides may serve as an easy-to-access indicator of both systemic involvement and prognostic outcome in dermato/rheumatologic disorders. This review will focus on clinical and histopathological findings of panniculitides in the setting of dermato/rheumatologic disorders and discusses the value of skin biopsies and consequent histopathological examination in the diagnosis of these disorders with the help of a logarithmic table.