Diffuse alveolar haemorrhage (DAH) complicating primary catastrophic anti-phospholipid syndrome (CAPS) was diagnosed in a 50-year-old female patient. Treatment strategies are limited for this often life-threatening autoimmune disease that requires aggressive immunosuppression. In the absence of clinically validated treatment strategies, high-dose steroids associated with plasma exchange and eventually intravenous immunoglobulins were used to manage the disease. Its severity prompted the initiation of rituximab that was administered weekly for four consecutive weeks. Anticoagulation therapy, on the other hand, needed to be discontinued due to the major haemorrhagic episodes. This combination treatment provided an effective control of the CAPS-associated DAH and helped achieve clinical remission.