This case was reported in a literature article and described the occurrence of hypersensitivity syndrome in a 62-year-old female patient who received Seasonal Influenza vaccine. Co-suspect products included azathioprine unknown for autoimmune hepatitis. Concurrent medical conditions included autoimmune hepatitis. Concomitant products included mycophenolate mofetil. On an unknown date, the patient received Seasonal Influenza vaccine at an unknown dose and azathioprine (unknown) at an unknown dose and frequency. On an unknown date, 4 days after receiving Seasonal Influenza vaccine and 10 days after starting azathioprine, the patient experienced hypersensitivity syndrome (serious criteria hospitalization and GSK medically significant), urosepsis (serious criteria GSK medically significant), fever, fatigue, myalgia, papulopustular rash, leukocytosis, cloudy urine, hypercreatininemia and neutrophilic dermatosis. The patient was treated with prednisone, cefepime and Antibiotics (Drug Name Unknown). The action taken with azathioprine was unknown (Dechallenge was unknown). Rechallenge with azathioprine was unknown. On an unknown date, the outcome of the hypersensitivity syndrome, urosepsis, fever, fatigue, myalgia, papulopustular rash, leukocytosis, cloudy urine, hypercreatininemia and neutrophilic dermatosis were recovering/resolving. It was unknown if the reporter considered the hypersensitivity syndrome, urosepsis, fever, fatigue, myalgia, papulopustular rash, leukocytosis, cloudy urine, hypercreatininemia and neutrophilic dermatosis to be related to Seasonal Influenza vaccine. The reporter considered the hypersensitivity syndrome, urosepsis, fever, fatigue, myalgia, papulopustular rash, leukocytosis, cloudy urine, hypercreatininemia and neutrophilic dermatosis to be related to azathioprine. Additional information received: This case was reported in a literature article and it described the occurrence of azathioprine hypersensitivity syndrome in a 62-year-old female patient who had received unspecified influenza vaccine (manufacturer unknown). The patient had a history of autoimmune hepatitis, on chronic immunosuppressive therapy. The patient had switched from mycophenolate mofetil to azathioprine 10 days before hospitalization. The patient denied any recent travel, localizing symptoms of infection, or known exposure to sick contacts. No further information on his medical or family history or concurrent condition was provided. On an unspecified date, the patient received influenza vaccine (administration route and site unspecified; dosage unknown; batch number not provided). On an unspecified date, 1 week after receiving the vaccine, she was admitted to hospital with a 3-day history of fever, fatigue, diffuse myalgias, and a new asymptomatic rash. Prednisone was continued at 10 mg/d. The patient had a temperature of 39.5 degrees C, an increased white blood cell count of 27,000 cells/ul with a left shift, and turbid urine. Creatinine was elevated to 2.6 mg/dl. Liver enzymes and bilirubin were unchanged from the patient's baseline levels. Physical examination revealed multiple erythematous, edematous papules with central deep-seated pustules on the right upper eyelid, bilateral cheeks, trunk, and proximal extremities. The mucosal surfaces were uninvolved. A punch biopsy was obtained from the right upper arm. Histologic evaluation revealed a subcorneal pustule with interstitial and perivascular neutrophilic inflammation. There was no significant papillary dermal edema. Gram and periodic acid-Schiff stains were negative. Overall findings were most consistent with a neutrophilic dermatosis secondary to azathioprine hypersensitivity. Azathioprine was stopped shortly after admission. This was a serious case as it required hospitalisation. Treatment consisted initially of continuation on prednisone 10 mg/d and start on intravenous cefepime of presumed urosepsis. However, the antibiotic was discontinued after two days as the patient had no symptoms of dysuria, and both blood and urine cultures remained negative. A wound culture obtained from pustular contents was also negative. The patient's rash and laboratory abnormalities improved significantly over the course of a 4-day hospital stay. The outcome of the event was improving at the time of reporting. The authors considered causality relationship between azathioprine and the event as final diagnosis was azathioprine hypersensitivity syndrome. The authors conclusion involved aspects related with azathioprine hypersensitivity syndrome.