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Panniculitis

»What is panniculitis?
»Name the various types of panniculitis. How are they classified?
»What is erythema nodosum?
»What is the pathogenesis of erythema nodosum?
»List some of the common underlying conditions associated with erythema nodosum.
»How should a biopsy of erythema nodosum be obtained?
»What are the characteristic microscopic features of erythema nodosum?
»How is erythema nodosum treated?
»What is nodular vasculitis?
»What causes nodular vasculitis?
»Describe the microscopic features of nodular vasculitis.
»What is the differential diagnosis of nodular vasculitis?
»How should nodular vasculitis be treated?
»What are the clinical features of lupus panniculitis?
»Describe the microscopic features of lupus panniculitis.
»What is the significance of diagnosing lupus panniculitis?
»Are sclerema neonatorum and subcutaneous fat necrosis of the newborn the same thing?
»How similar are the microscopic features of sclerema neonatorum and subcutaneous fat necrosis of the newborn?
»Why do these disorders occur in neonates and infants?
»What is pancreatic fat necrosis?
»Are there any characteristic histopathologic features of pancreatic fat necrosis?
»What is the role of a-1 antitrypsin deficiency in the development of panniculitis?
»Name some types of trauma that can produce panniculitis.
»Which infectious organisms can produce panniculitis?
»Describe the role of malignancy in producing panniculitis.
»What is lipodystrophy?
»What is lipoatrophy?
»What is lipohypertrophy?
»Discuss the approach to use when attempting to diagnose an “unknown” case of panniculitis.

 
 
 

What is erythema nodosum?

Typical lesion of erythema nodosum on the leg. Erythema nodosum heals without scarring. (Courtesy of James E. Fitzpatrick, MD.)
Fig. 19.1 Typical lesion of erythema nodosum on the leg. Erythema nodosum heals without scarring. (Courtesy of James E. Fitzpatrick, MD.)
Erythema nodosum (Fig. 19-1) consists of an eruption of erythematous, tender nodules— typically over the pretibial areas but occasionally elsewhere—that is regarded as a hypersensitivity response to some antigenic challenge. It is typically an acute process lasting 3 to 6 weeks, but a more chronic form can occur. Some experts consider the condition termed subacute nodular migratory panniculitis (Vilanova’s disease) to be a chronic variant of erythema nodosum.

Requena L, Yus ES: Panniculitis. Part I. Mostly septal panniculitis, J Am Acad Dermatol 45:163–683, 2001.