Inflammatory leg nodules: A clinical and investigational study.

BACKGROUND: Inflammatory leg nodules are a diagnostically challenging group of dermatoses with limited tools for diagnosis. Considerable overlapping patterns exist despite their distinct clinical and histological features. We attempted to understand if undertaking investigations and studying the clinical course and treatment response can help in differentiating these dermatoses.

METHODS: Forty-three patients presenting with inflammatory leg nodules underwent a series of investigations apart from histopathology. The patients were treated as per the final histological diagnosis and observed for response to treatment and followed up to evaluate the clinical course.

RESULTS: There was considerable overlap in the investigations done among various dermatoses. These included elevated erythrocyte sedimentation rate (ESR), Mantoux test and antistreptolysin- O (ASLO) titres in the majority of patients while a few had abnormal findings on chest X-ray, CT scan of the chest and doppler ultrasonography of the legs. About 86% of patients with erythema nodosum, 50% with erythema induratum, 57% with cutaneous medium vessel vasculitis and 93% with unclassified panniculitis responded to non-steroidal non-inflammatory drugs (NSAIDs) alone or had spontaneously resolved with only post-inflammatory hyperpigmentation. Other patients required specific treatment with immunosuppressive or immunomodulatory agents.

CONCLUSIONS: There is considerable overlap in dermatoses manifesting as inflammatory leg nodules on investigations, treatment received and response to treatment. To categorize them better into distinct entities, this group of dermatoses may require long-term follow-up of the clinical course and response to treatment, repeated investigations especially histopathology during different phases of evolution and progression of disease.