Panniculitis in Adult
See also in: Cellulitis DDxAlerts and Notices
Synopsis

Panniculitis is a collective term for a group of inflammatory diseases involving subcutaneous fat. The panniculitides are subdivided histologically based on the location of the predominant amount of inflammation: in the intralobular septa or within the fat lobule itself. A mixture of patterns may also be seen (septal and lobular). Most share a common presentation of tender dermal or subcutaneous nodules, papules, or plaques. They all may be mistaken for cellulitis.
Erythema nodosum (EN) is by far the most common type of panniculitis and one of few mainly involving the septa (septal panniculitis). Other rarer types of panniculitis are generally classified as more lobular in nature and include infectious (necrotizing granulomatous) panniculitis, a panniculitis associated with systemic lupus erythematosus (lupus profundus), Weber-Christian disease, nodular vasculitis (erythema induratum), pancreatic panniculitis, cytophagic histiocytic panniculitis, and α1-antitrypsin deficiency panniculitis. There are also physical forms of panniculitis (cold panniculitis, factitial panniculitis). Furthermore, other diseases may be associated with a secondary panniculitis (necrobiosis lipoidica, polyarteritis nodosa, and some vasculitides).
EN is an inflammatory reaction pattern, sometimes precipitated by identifiable endogenous or exogenous stimuli. Streptococcal infections are the most common etiologic factor in children, while sarcoidosis, inflammatory bowel disease, and drugs are more commonly implicated in adults. Most cases are idiopathic. The eruption persists for 3–6 weeks and spontaneously regresses without scarring or atrophy. Fever with generalized aching sometimes accompanies the onset of skin lesions. EN can occur at any age, but most cases occur between the ages of 20 and 45. It is more common in women.
Panniculitis can be distinguished from cellulitis because it most often occurs bilaterally and lesions are often multifocal.
Erythema nodosum (EN) is by far the most common type of panniculitis and one of few mainly involving the septa (septal panniculitis). Other rarer types of panniculitis are generally classified as more lobular in nature and include infectious (necrotizing granulomatous) panniculitis, a panniculitis associated with systemic lupus erythematosus (lupus profundus), Weber-Christian disease, nodular vasculitis (erythema induratum), pancreatic panniculitis, cytophagic histiocytic panniculitis, and α1-antitrypsin deficiency panniculitis. There are also physical forms of panniculitis (cold panniculitis, factitial panniculitis). Furthermore, other diseases may be associated with a secondary panniculitis (necrobiosis lipoidica, polyarteritis nodosa, and some vasculitides).
EN is an inflammatory reaction pattern, sometimes precipitated by identifiable endogenous or exogenous stimuli. Streptococcal infections are the most common etiologic factor in children, while sarcoidosis, inflammatory bowel disease, and drugs are more commonly implicated in adults. Most cases are idiopathic. The eruption persists for 3–6 weeks and spontaneously regresses without scarring or atrophy. Fever with generalized aching sometimes accompanies the onset of skin lesions. EN can occur at any age, but most cases occur between the ages of 20 and 45. It is more common in women.
Panniculitis can be distinguished from cellulitis because it most often occurs bilaterally and lesions are often multifocal.
Codes
ICD10CM:
M79.3 – Panniculitis, unspecified
SNOMEDCT:
22125009 – Panniculitis
M79.3 – Panniculitis, unspecified
SNOMEDCT:
22125009 – Panniculitis
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Cellulitis or erysipelas
- Stasis dermatitis
- Contact dermatitis
- If ulceration is a feature, the ulcers may be confused with ulceration that is vascular, pressure-induced (decubitus), or neurogenic (diabetic) in nature.
- Sarcoidosis
- Subcutaneous granuloma annulare
- Rheumatoid nodules
- Vasculitis
- Eosinophilic cellulitis
- Insect bites (arthropod bites)
- Sweet syndrome
- Pretibial myxedema
- Necrobiosis lipoidica
- Pseudolymphoma and some forms of lymphoma can mimic panniculitis.
- Leprosy
- Traumatic fat necrosis
- Subcutaneous panniculitis-like T-cell lymphoma
- Radiation dermatitis
- Lipodermatosclerosis
- Botryomycosis
- Majocchi granuloma
- Pyoderma gangrenosum
- Superficial thrombophlebitis
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
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References
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Last Updated:10/03/2016
Panniculitis in Adult
See also in: Cellulitis DDx