| Table 3-22 Panniculitides |
| | Disease | | Clinical Findings | | Pathology | | Associations |
| | Erythema
nodosum (EN)
{Positive prognostic factor in sarcoidosis and coccidioidomycosis}
{Do not confuse with erythema nodosum leprosum (vasculitis)} | | Delayed hypersensitivity response with painful, erythematous subcutaneous nodules commonly over pretibial areas → progress to bruise-like color, ± fever, arthralgias, malaise
Typically self-limited | | Septal panniculitis; edematous widened septae with giant cells, neutrophils → later see lymphocytes, ± septal fibrosis, foamy histiocytes, Miescher’s microgranulomas (clusters of histiocytes surrounding clefts) | | Idiopathic (30%), strep infection (also viral, deep fungal), sarcoidosis, drugs (OCP, sulfonamides), Behçet’s, malignancy
IBD (Crohn’s > UC)
{Per Bolognia and Harrison}
Treatment (dependent on etiology): bed rest, NSAID, colchicine, potassium iodide (KI) |
| | Subacute nodular migratory panniculitis (EN migrans) | | Nodules that migrate or expand centrifugally, often unilateral; chronic course | | Chronic septal panniculitis with greater septal thickening than EN | | Most idiopathic, ± associated strep infection or thyroid disease
Treatment: KI |
| | Morphea/scleroderma panniculitis | | Deep indurated plaques typically over extremities | | Septal panniculitis with mucin, thickened septae, lymphocytes and plasma cells | | Treatment: see section on morphea |
| | Erythema induratum (Bazin’s disease) | | Erythematous plaques or nodules commonly over calves {Unlike shin location of EN}, ± ulceration, drainage | | Lobular or mixed panniculitis: mixed infiltrate (histiocytes, lymphocytes, giant cells, plasma cells), vasculitis often in fat, ± caseation necrosis, fibrosis later | | Associated with tuberculosis; if no TB association, termed ‘nodular vasculitis’
Treat underlying TB |
| | α-1-antitrypsin deficiency panniculitis
{α 1-antitrypsin: major protease inhibitor in serum} | | Erythematous, tender subcutaneous nodules that often ulcerate with oily discharge; commonly in lower trunk and extremities, ± fever, pleural effusion, pulmonary embolism | | Lobular panniculitis with neutrophils and lymphocytes, liquefactive necrosis of fat (foamy macrophages, ± cystic spaces), ‘skip areas’ of normal fat next to necrotizing area | | Deficiency of α 1AT
May have associated chronic liver disease, emphysema, pancreatitis, angioedema, glomerulonephritis |
| | Pancreatic panniculitis (Pancreatic fat necrosis) | | Subcutaneous nodules often on legs (± trunk, arms, scalp), ± oily discharge; ± fever, abdominal pain, arthralgias, ascites | | Septal panniculitis → lobular or mixed with fat necrosis and ‘ghost-like’ lipocytes, basophilic calcium deposition in fat | | Pancreatitis and pancreatic carcinoma
Amylase levels peak 2–3 days after eruption |
| | Post-steroid panniculitis | | Firm, red plaques on cheeks, trunk and arms, ± associated pruritus or tenderness | | Predominantly lobular panniculitis, needle-shaped clefts in lipocytes or giant cells | | Occurs after rapid withdrawal of systemic corticosteroids |
| | Lupus panniculitis (Lupus profundus) | | Tender, subcutaneous plaques and nodules on face, upper outer arms, trunk, shoulders and hips, ‘tethered’ depressed appearance; chronic, relapsing nature | | Lobular panniculitis: hyaline necrosis of fat lobules, ± mucin, ‘lymphoid follicles’ (aggregates of lymphocytes), ± LE epidermal changes, ± vasculitis | | Typically occurs antecedent to other manifestations of LE, closer relationship to CCLE than SLE
Treatment: antimalarials often |
| | Cold panniculitis (Equestrian or popsicle panniculitis) | | Erythematous, firm nodules or plaques typically over cheeks and chin (can be on outer thighs in equestrian panniculitis) | | Lobular panniculitis with mixed infiltrate, perivascular dermal lymphocytic infiltrate with ↑↑ inflammation at dermal-subQ junction, + mucin, cystic spaces in fat | | Usually infants and children exposed to cold (i.e. weather, cold food such as popsicle)
Self-limited |
| | Sclerosing lipogranuloma (Paraffinoma) | | Pain and erythema with induration, ± ulceration with oily discharge, often involving the penis or scrotum | | Granulomatous lobular panniculitis with ↑ fibrosis, many round vacuoles of varying sizes in dermis and subcutis (‘Swiss-cheese’) | | Usually due to self-injection of oily materials (paraffin or silicone)
Treatment: excision if small |
| | Factitial panniculitis | | Inflamed nodules (etiology hinted by distribution of lesions) | | Central nidus of subcutaneous inflammation | | Typically self-inflicted by psychiatric patients |
| | Lipodermatosclerosis (Sclerosing panniculitis) | | Wood-like induration, hyperpigmentation and erythema on lower legs bilaterally (‘inverted wine bottle’) | | Thickening of dermis and septae, microcysts in lobules, cyst wall with PAS + cuticle-like eosinophilic membrane, pericapillary fibrin | | Associated with chronic venous insufficiency
Treatment: compression therapy, pentoxifylline, stanozolol |
| | Cytophagic histiocytic panniculitis | | Subcutaneous nodules ± ulceration on trunk/extremities; fulminant systemic disease with fever, liver failure, DIC, pancytopyenia | | Mixed panniculitis: macrophages (called ‘bean bag’ cells) contain erythrocytes, lymphocytes or karyorrhectic debris (cytophagocytosis) | | Most cases associated with T cell lymphoma (specifically subcutaneous panniculitis- like T cell lymphoma) |
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