This literature marketed report as received from other health professional for which learning objectives was to understand common reactions to the PNEUMOVAX 23 and to recognize the role of streptococcal antigens in Behcet's disease. The patient refers to 41 year old male with a history of Behcet's disease treated with azathioprine presented with one day of fevers, rigors and severe right arm and shoulder pain. His symptoms started 12 hours after receiving the PNEUMOVAX 23 in his right deltoid. Vital signs on admission were notable for temperature of 104.8 degrees Fahrenheit and heart rate of 120 (units not provided). There was full range of motion at the shoulders. There was a 12 centimeter poorly demarcated area of erythema, warmth, fullness, and exquisite tenderness to palpation over the right deltoid. Labs were notable for C-reactive protein of 24 mg/dL and white blood cell count of 20,000. Blood cultures showed no growth. A sonogram of the right deltoid was unremarkable. He was treated supportively with intravenous fluids and acetaminophen. By hospital day two his arm pain and fevers had resolved, and he was discharged home without further incident. Behcet's disease is a rheumatological condition found most commonly in those of Turkish or Middle Eastern descent. Behcet's may cause vasculitis of vessels of all sizes, and classically manifests as recurrent oral, genital and skin ulcerations. It may also involve the brain, heart, kidneys, lungs, joints and eyes and can progress to blindness, severe gastrointestinal bleeding, and permanent neurological deficits. Treatment depends on the extent of disease progression, but generally requires immunosuppression with glucocorticoids followed by azathioprine, infliximab or cyclosporine. The Centers of Disease Control and Prevention recommend administration of the PNEUMOVAX 23 to immunocompromised adults, including those patients taking immunomodulating agents. About 50% of adults will experience mild reactions to this vaccine, usually a local inflammatory response at the site of injection. Systemic reactions, including fevers and arthralgias, occur in less than 1% of recipients. Severe reactions, such as seen in this patient, are exceedingly rare. To authors knowledge, this was the fifth reported case of a severe systemic inflammatory response after administration of the PNEUMOVAX 23 in a patient with Behcet's disease. As in our patient, symptoms mostly resolved by 48 hours with supportive care. Of particular interest are streptococcal species. When compared to controls, Behcet's patients have significantly higher titers against certain species of streptococcus. Exposure to these antigens, such as from skin testing, causes upregulation of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha which in turn can lead to hypersensitivity reactions and exacerbations of Behcet's. Hypersensitivity reactions to streptococcal antigens are frequent enough that is part of the foreign diagnostic criteria for Behcet's. The reporter considered severe systemic inflammatory response (hospitalisation) to be related to PNEUMOVAX 23. The outcome of the event was assessed as recovered/resolved. Additional information has been requested.