Erythema nodosum

This code represents an inflammatory condition characterized by tender, red nodules, typically found on the shins. It is a panniculitis, meaning the inflammation primarily affects the subcutaneous fat layer. Erythema nodosum is often a reactive process, associated with various underlying systemic conditions, infections, or medications.

Use this code when documentation explicitly states a diagnosis of erythema nodosum. This diagnosis is often made clinically based on the characteristic skin lesions and may be supported by a skin biopsy showing septal panniculitis without vasculitis. It is crucial to also code any identified underlying cause.

• Always search for and code any associated underlying condition (e.g., streptococcal infection, sarcoidosis, inflammatory bowel disease) as a primary or secondary diagnosis.
• Do not confuse with other forms of panniculitis or other nodular skin conditions; a definitive diagnosis of erythema nodosum is required.
• Review provider documentation for details on the etiology to ensure comprehensive coding.