Diffuse orbital inflammation: an atypical manifestation of Behcet's disease.

Behcet's disease is a chronic, relapsing systemic vasculitis characterised by multisystem involvement from small, medium and large vessel inflammation. Common manifestations include oral and genital ulcers, rash, uveitis and neurological symptoms, while orbital inflammation is rare. An Asian man in his 40s with Behcet's disease on immunosuppression presented with 10 days of unilateral periorbital swelling and painful eye movements, unresponsive to oral antibiotics. Imaging revealed diffuse orbital inflammation and optic neuritis. Investigations excluded an infectious cause. Despite broad-spectrum intravenous antibiotics, his condition worsened until typical Behcet's disease mucocutaneous symptoms emerged, indicating a Behcet's flare. Treatment with high-dose corticosteroids, followed by cyclophosphamide and azathioprine resolved the diffuse orbital inflammation. Unfortunately, the visual outcome was poor as he remained blind in the affected eye from optic neuritis and corneal ulceration. This case highlights the importance of early diagnosis and treatment of diffuse orbital inflammation in Behcet's disease to prevent severe ocular complications.