Panniculitis was first described in the nineteenth century and is characterized by
inflammation of the subcutaneous fat. It may be categorized in septal or lobular subtypes, but other histopathological features (e.g., presence of
vasculitis, nature of inflammatory infiltrates, characteristics of
fat necrosis) are also important for diagnostic purposes. Clinically,
panniculitis is characterized by the presence of subcutaneous nodules, and both ulcerative and nonulcerative clinical subtypes have been proposed. In this review, we aimed to describe the occurrence of
panniculitis in autoinflammatory disorders (
AIDs) and related diseases. Among monogenic
AIDs,
panniculitis is common in IFN-mediated disorders.
Panniculitis is a distinctive feature in
proteasome-associated autoinflammatory syndromes (PRAAS), including
chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and Nakajo-Nishimura syndrome. On the other hand,
erythema nodosum corresponds to the most common clinical form of
panniculitis and is common in polygenic
AIDs, such as Behçet's syndrome,
inflammatory bowel disease, and
sarcoidosis. Cytophagic histiocytic
panniculitis, lipoatrophic
panniculitis of children, and otulipenia are rare disorders that may also present with
inflammation of the subcutaneous fat. Therefore,
panniculitis can identify a specific subgroup of patients with
AIDs and may potentially be regarded as a cardinal sign of autoinflammation.