Purpose: To define the epidemiology and clinical features of Behçet's disease, giving special attention to unusual forms.
Methods: We retrospectively reviewed the medical records of 309 cases with joint manifestations among 450 cases of Behçet's disease seen over a 20-year period who met the International Study Group of Behçet's disease criteria.
Results: Joint manifestations were present in 68.3% and were inaugural in 34.5%. The knee and ankles were the joints most commonly affected. Monoarthritis, oligoarthritis and polyarthritis were seen respectively in 12, 13.5 and 19.8%. Sacroiliitis is observed in 6%. Unusual forms included destructive polyarthritis (two cases), popliteal cyst (two cases), myositis (two cases) and ankylosing spondylitis (two cases).
Conclusion: Joint manifestations are common in Behçet's disease. They are frequently associated with erythema nodosum and necrotic pseudofolliculitis. Polyarthritis is not rare. Their unusual forms deserve to be known.