rgkulkarni, MD, Emergency Medicine, 05:53PM Mar 31, 2011
Rick G. Kulkarni, MD, Vice President/Medical Director, WebMD
A 45-year-old woman presents to the emergency department (ED) with a 2-day history of an acute-onset, mildly pruritic rash. The rash started in her axillae and groin and has since progressed to the rest of her body. She then developed a fever this morning. She was diagnosed with pneumonia 4 days ago and has been taking azithromycin since that time. She was previously in good health, and her past medical history and family history are negative for psoriasis, arthritis, and other significant medical conditions. She has no known history of drug allergies. She does not smoke and drinks an average of 2 glasses of wine each week. She is a teacher, and she has 2 young children at home.
On physical examination, the patient appears to be in no acute distress. Her vital signs include a temperature of 102.0°F (38.9°C), a pulse rate of 88 bpm, a blood pressure of 124/76 mm Hg, and a respiratory rate of 16 breaths/min. Fine crackles are auscultated in the left lower lung field. A complete skin examination reveals hundreds of nonfollicular pustules on erythematous bases diffusely spread over her face, trunk, axillae, groin, arms, and legs. The lesions are without any crust or scale. No lesions are observed on her palms, soles, or mucous membranes. The remainder of the physical examination is unremarkable.
Laboratory tests are obtained. The white blood cell count is elevated at 16 × 109 cells/L (normal range, 4.3-10.8 × 109 cells/L), with a moderately elevated total neutrophil count of 14 × 109 cells/L (normal range, 1.3-6.7 × 109 mg/L) and a slightly elevated eosinophil count of 0.37 × 109 cells/L (normal range, 0.0-0.3 × 109 cells/L). The C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are also elevated, at 84 mg/L (normal range, <10 mg/L) and 34 mm/hr (normal range, 0-19 mm/hr), respectively. Blood cultures are positive for Mycoplasma pneumoniae but negative for additional bacteria or fungi. Culture and Gram stain of several pustules are obtained and are negative. A punch biopsy of a pustule on her leg is performed. The histology shows spongiform subcorneal pustules, edema of the papillary dermis, marked perivascular infiltration of neutrophils, and exocytosis of a few eosinophils. A clinical picture of the lesions appears here. The patient has taken azithromycin once in the past for an unrelated condition with no adverse effects.
What is the diagnosis? How would you approach this patient's treatment?
Our thanks are extended to Tiffany Kwok, BHSc, and Benjamin Barankin, MD, FRCPC, for providing the details of this case, and to Adam Perrin, MD, for reviewing this content.
See comment #30 for the diagnosis and a discussion of this condition.
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