A cenocoumarol is an effective oral coumarin anticoagu- lant. Bleeding is the main adverse effect of aceno- coumarol therapy; dysphagia, vasculitis, and cerebral infarc- tion have also been reported. 1 Cutaneous adverse effects of oral anticoagulant therapy, such as skin rash, photosensi- tivity, vasculitis, and skin tissue necrosis, have been de- scribed. 2 We present a patient with Henoch–Schönlein pur- pura following treatment with acenocoumarol. To our knowledge, there has been no previous mention of this as- sociation in the literature. Case Report A 76-year-old white woman with no significant past medical or surgical history and no history of allergy to drugs was referred to our emergency department (ED) because of hematemesis. Two months before admission, she started treatment with oral acenocoumarol 12 mg/wk for chronic atrial fibrillation. One month after starting treatment, the patient developed a maculopapular purpuric rash on the trunk, arms, and lower extremities that was treated by her community physician with oral prednisone 10 mg/day with partial improvement. She was taking no other medications and did not develop an infection during the time that she received acenocoumarol. In the ED the patient developed abdominal pain associated with vom- iting. Physical examination revealed multiple round, confluent, purpuric lesions with some vesicles and an area of residual pigmentation. Lesions were present predominantly on the legs and gluteus, and also on the trunk and arms (Figure 1). On admission to the hospital, laboratory test- ing showed hemoglobin 13.5 g/dL, hematocrit 41%, and white blood cell count 19.8 × 10 3 /mm 3 . Glucose, creatinine, iron, serum liver en- zymes, thyroid function tests, erythrocyte sedimentation rate, serum pro- tein immunoelectrophoresis, immunoglobulins, and complement were normal. The platelet count was also within normal limits. The prothrom- bin time, international normalized ratio (INR), and partial thromboplas- tin time were in the desired therapeutic range. Rheumatoid factor, antinu- clear antibodies, cryoglobulins, anticardiolipin antibodies, antineutrophil cytoplasmic antibody (cytoplasmic pattern), antineutrophil cytoplasmic The Annals of Pharmacotherapy ■ 2004 February, Volume 38 ■ 261 Acenocoumarol–Induced Henoch–Schönlein Purpura Joaquín Borrás-Blasco, Eva Girona, Andrés Navarro-Ruiz, Jaime Matarredona, María Encarnación Giménez, Ana Gutiérrez, Ricardo Enriquez, and Antonio Martinez www.theannals.com Author information provided at the end of the text. OBJECTIVE: To report a probable case of Henoch–Schönlein purpura associated with acenocoumarol therapy. CASE SUMMARY : A 76-year-old white woman was prescribed acenocoumarol for chronic atrial fibrillation. Two months after starting therapy, the patient came to our hospital’s emergency department because of abdominal pain associated with vomiting. Physical examination revealed multiple round, confluent, purpuric lesions with some vesicles and an area of residual pigmentation. Lesions were present predominantly on the legs and gluteus, and also on the abdomen and arms. Skin biopsy of the lesions was compatible with leukocytoclastic vasculitis with deposition of immunoglobulin A. An upper intestinal endoscopy was done and identified purpuric mucosal lesions in the fundus, body, and antrum of the stomach and the duodenal bulb. Renal function was not affected, although proteinuria (1.26 g/day) was found and microscopic hematuria was observed. DISCUSSION: The most likely cause of the Henoch–Schönlein purpura in this case was considered to be acenocoumarol because of the close temporal relationship between exposure to the drug and onset of symptoms, as well as the rapid resolution of the symptoms and signs after acenocoumarol was discontinued. The oral anticoagulant was the only identifiable precipitant that the patient encountered before the Henoch–Schönlein purpura developed. An objective causality assessment revealed that the adverse drug event was probable. CONCLUSIONS: This case report illustrates a probable association between Henoch–Schönlein purpura and acenocoumarol. As of December 2003, this reaction had not been previously reported. Clinicians should be aware of this potential adverse effect of a widely used drug. KEY WORDS: acenocoumarol, Henoch–Schönlein purpura. Ann Pharmacother 2004;38:261-4. Published Online, 23 Dec 2003, www.theannals.com, DOI 10.1345/aph.1D270 by guest on October 11, 2013 aop.sagepub.com Downloaded from by guest on October 11, 2013 aop.sagepub.com Downloaded from by guest on October 11, 2013 aop.sagepub.com Downloaded from by guest on October 11, 2013 aop.sagepub.com Downloaded from