[Septicemia due to methicillin-resistant Staphylococcus aureus from chronic prurigo in an elderly woman]

An 80-year-old woman being treated with anti-hypertensive drugs developed eruption and itching of the skin. High fever and lymph node enlargement subsequently developed in spite of discontinuing all antihypertensive drugs, and she was admitted to our hospital. At the initial examination, multiple papules were noted over the entire body, and the skin showed thickening and lichenification with scratch marks. There was also generalized enlargement of the superficial lymph nodes. From these findings, her condition was diagnosed as chronic prurigo due to drug allergy. Laboratory tests showed inflammatory findings, anemia and a high serum level of IgE. Analysis of the surface marker of peripheral lymphocytes revealed no abnormalities. Bacteriologic cultures of blood revealed methicillin-resistant Staphylococcus aureus (MRSA). Histologic examination of the lymph nodes revealed chronic reactive lymphadenitis with a follicular pattern. She was strongly suspected of having MRSA septicemia, and so combination chemotherapy with vancomycin, minocycline and cefoperazone/sulbactam was started. However, 1 month after initiation of chemotherapy, the low-grade fever, eruption and moderate inflammatory findings persisted, and culture of the eruptions revealed MRSA. The prurigo was therefore considered to be the source of the septicemia, and daily application of diflucortolone ointment containing 3% acetic acid was started. Thereafter, the clinical and laboratory findings showed a rapid improvement. MRSA infections usually occur in compromised patients who are receiving antibiotics during prolonged hospitalization. The present case, who did not have any underlying disease, indicates that old-age is also an important factor for the development of MRSA septicemia.