Ulcerative versus non-ulcerative panniculitis: is it time for a novel clinical approach to panniculitis?

Approach to the Atypical Wound

The heterogeneity of atypical wounds can present diagnostic and therapeutic challenges; however, as the prevalence of atypical wounds grows worldwide, prompt and accurate management is increasingly an essential skill for dermatologists. Addressing the underlying cause of an atypical wound is critical for successful outcomes. An integrated approach with a focus on pain management and patient engagement is recommended to facilitate enduring wound closure. Advances in treatment, in addition to further research and clinical training, are necessary to address the expanding burden of atypical wounds.

Neutrophilic Panniculitides

Neutrophilic panniculitides are a heterogeneous group of inflammatory disorders encompassing many different entities. This review article focuses on the epidemiology, pathogenesis, clinicopathological features, diagnosis, and treatment of selected diseases. Patients often seek care due to systemic involvement, but the variable presentation of panniculitides can present a diagnostic challenge. Most therapeutic modalities for neutrophilic disorders are anecdotal at best with a notable lack of standardization of the responses to medications. There is an urgent need for a larger multi-institutional collaboration to address the unmet needs of these challenging, yet rare conditions.

Panniculitis: A Cardinal Sign of Autoinflammation

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.

Suggestions for a New Clinical Classification Approach to Panniculitis Based on a Mayo Clinic Experience of 207 Cases

BACKGROUND

Panniculitis, or inflammation of adipose tissue, includes a heterogeneous group of disorders with similar morphologic presentations. Currently, panniculitides are classified based on histopathologic findings only.

OBJECTIVE

In this retrospective study of 207 cases of biopsy-proven panniculitis over 20 years at Mayo Clinic, we aimed to propose a new classification that integrates the clinical morphologic features with the histopathology of panniculitis.

METHODS

We collected patient demographic and lesion morphologic characteristics using lesion photographs and physician notes for each of our 207 cases, including location, ulceration, scale, pattern (unilateral versus circumferential), atrophy/sclerosis (cicatricial), redness, and swelling.

RESULTS

The panniculitides most likely to ulcerate were calciphylaxis (85.7% ulcerating), pancreatic panniculitis (66.6%), and α₁-antitrypsin deficiency-associated panniculitis (100%). The panniculitides least likely to ulcerate were erythema nodosum and medication-induced and granulomatous panniculitis. This retrospective study used only descriptions in clinical notes and available medical photographs.

CONCLUSION

We present an updated classification schema of panniculitides based on clinical findings. The primary distinctions are based on ulceration, location, and number of lesions. Although complete distinction of all panniculitides based on clinical examination alone is not possible, we hope the proposed schema allows clinicians to tailor differential diagnoses.