DeCure for Panniculitis

Panniculitis is inflammation of subcutaneous fat, classified histologically as septal or lobular, with or without vasculitis, and caused by infection, immune-mediated disorders, malignancy, drugs, enzyme deficiency, or trauma. A 2007 review notes that surgical biopsy of a fresh lesion is essential for correct histopathological diagnosis. In connective tissue disease, both specific and nonspecific panniculitis occur, and a 1983 paper states that microscopic studies of epidermis and dermis, immunofluorescent microscopy, and serologic testing may aid diagnosis; it also suggests that connective tissue panniculitis and focal lipoatrophy may be forms of immunoreactive panniculitis or connective tissue disease in which typical events of classic connective tissue disease have not occurred.

Panniculitis is a common histopathological feature of cutaneous leishmaniasis. A 2017 case series of 35 patients (18 women, 17 men, mean disease duration 3 months) found panniculitis in 16 cases (46%), appearing as diffuse lymphohistiocytic infiltration of both septum and lobules of the subcutaneous layer. The authors state that panniculitis in cutaneous leishmaniasis must be differentiated from other diseases such as chronic skin infections, discoid lupus erythematosus, and cutaneous lymphoma. In a separate 2018 case report, a 48-year-old man with new-onset diabetes and a mesenteric mass on CT compatible with mesenteric panniculitis later developed autoimmune diabetes confirmed by glutamic acid decarboxylase auto-antibodies; the authors note this is the first report correlating mesenteric panniculitis with autoimmune diabetes.

In advanced melanoma treated with BRAF and MEK inhibitors, panniculitis has been hypothesised to predict better survival, but a 2023 retrospective single-centre study of 10 patients who developed panniculitis matched to 26 controls found no significant association. Median progression-free survival for the panniculitis group was 10.5 months (range 7.0–undefined) versus 7.0 months (6.0–32.0) for controls (p=0.39). The prevalence of panniculitis was 5.3%. A systematic review of BRAF-inhibitor induced panniculitis, also from 2023, describes it as a mild cutaneous adverse reaction that may benefit from symptomatic management without targeted therapy cessation; the review notes that half of reported cases occur in the first month, that panniculitis usually affects only the lower limbs or is associated with fever or arthralgia, and that systemic corticosteroids have not been proven effective. Discontinuation of targeted therapy is not required as spontaneous remission is usually experienced.

What is still missing are prospective studies with adequate sample sizes to determine whether panniculitis in any specific disease context has prognostic or therapeutic significance. The 2023 melanoma study is small and retrospective; the 2017 leishmaniasis series is descriptive; the 1983 connective tissue disease paper offers no treatment data. No randomised trial has tested any intervention for panniculitis itself, and no biomarker stratifies patients by likelihood of response. Funding for such trials, standardised histopathological classification, and prospective collection of panniculitis incidence in drug-treated cohorts are all lacking.