Isotretinoin-Induced Thrombocytosis

We report a case of thrombocytosis possibly associated with isotretinoin . The patient was a 19-year-old female who had severe acne vulgaris for 5 years. Systemic oral isotretinoin treatment was used daily at a dose of 0.5 mg/kg. All of the laboratory parameters were within normal limits, and the platelet count was 282,000 /μ L at the beginning of the treatment (reference range: 150,000 - 400,000 /μ L). In the following months, thrombocytosis (630,000 /μ L) was found, and the treatment was ended. The platelet count was in the normal range (343,000 /μ L) in the next monthly visit. The patient had no other illnesses or medications. The exact mechanism by which isotretinoin caused thrombocytosis in this patient is not clearly understood. To our knowledge, this case is the second case of isotretinoin -associated thrombocytosis. Clinicians who are prescribing isotretinoin should be aware of thrombocytosis, and a complete blood cell count with platelets should be part of the monthly monitoring routine in all patients receiving isotretinoin therapy. doi: http://dx.doi.org/ 10.14740 / jh140e J Hematol. 2014;3(2):61-62