Am Fam Physician. 2016 Apr 15;93(8):701-702.
A 22-year-old pregnant woman (gravida 2, para 1) presented with a sore throat and tonsillar exudates at eight weeks' gestation. Group A rapid streptococcus antigen test results were positive, and streptococcal pharyngitis was diagnosed. She was treated with amoxicillin. On the seventh day of antibiotic treatment, she returned to the clinic with a tender skin nodule on her left anterior leg, and a different antibiotic was prescribed.
On physical examination, the patient had a low-grade fever and multiple erythematous nodules on both of her shins (Figures 1 and 2). The nodules were tender but had no ulceration or drainage. After no response to two weeks of oral antibiotic therapy, she was admitted to the hospital and intravenous antibiotics were initiated. A wound culture had no bacterial growth, and a complete blood count was within normal limits.
Based on the patient's history, physical examination findings, and laboratory results, which one of the following is the most likely diagnosis?
A. Bacterial cellulitis
B. Erythema nodosum.
C. Polyarteritis nodosa.
REFERENCESshow all references
1. Blake T, Manahan M, Rodins K. Erythema nodosum - a review of an uncommon panniculitis. Dermatol Online J. 2014;20(4):22376....
2. Schwartz RA, Nervi SJ. Erythema nodosum: a sign of systemic disease. Am Fam Physician. 2007;75(5):695–700.
3. Stulberg DL, Penrod MA, Blatny RA. Common bacterial skin infections. Am Fam Physician. 2002;66(1):119–124.
4. Gota CE. Polyarteritis nodosa (PAN). Merck Manual Professional Version. http://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/vasculitis/polyarteritis-nodosa-%28pan%29. Accessed August 10, 2015.
5. Merola JF. Dermatologic manifestations of sarcoidosis. http://emedicine.medscape.com/article/1123970-overview. Accessed January 20, 2016.
This series is coordinated by John E. Delzell Jr., MD, MSPH, Assistant Medical Editor.
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