Inflammation in the subcutaneous fat affecting the connective tissue septa separating lobules of fat, or fat lobules themselves.
Erythema nodosum is the most common form.
Often associated with infections such as tuberculosis, beta hemolytic streptococci, coccidioidomycosis, histoplasmosis and leprosy, drug exposure including sulfonamides, oral contraceptives, sarcoidosis, inflammatory bowel disease, and malignancies.
Many cases without recognized etiology.
Many instances associated with subacute or chronic course.
Often involves the lower extremities.
Erythema induratum an uncommon type of panniculitis