Author: Dr Ian Coulson, Consultant Dermatologist and Editor-in-Chief (2025).
Edited by the DermNet content department.
This 14-year-old girl has developed tender, red swellings on her shins over the last two weeks. She is now finding walking painful.
There are multiple poorly-defined, round, erythematous nodules measuring 1-5 cm in diameter over the shins bilaterally.
The clinical features and duration suggest that this is erythema nodosum.
This is an inflammatory condition of subcutaneous fat tissue (panniculitis) thought to be caused by a hypersensitivity reaction. There are many potential triggers, including underlying sarcoidosis, inflammatory bowel disease, streptococcal infection, tuberculosis, drugs, and Behcet disease.
The history, examination, and investigations should search for an underlying trigger. In this case, her chest x-ray showed asymptomatic bilateral hilar lymphadenopathy. The erythema nodosum gradually subsided spontaneously over eight weeks. The underlying diagnosis was sarcoidosis, which was asymptomatic apart from the erythema nodosum.
