Abstract

A 79-year-old female presented with bilateral forearm purpura while on acalabrutinib (BTK-inhibitor) for 14 months for treatment of chronic lymphocytic leukemia (CLL). A skin biopsy demonstrated ecstatic dermal vasculature with superficial perivascular lymphoid infiltrate and extravasated erythrocytes. CD5 stain was positive in T cells as well as scattered B cells. She had no history of liver disease or coagulopathy and no concomitant use of anti-coagulants or anti-platelet medications. Acalabrutinib was discontinued and the purpura cleared. 

Cutaneous toxicities of BTK inhibitors have been reported to be one of the most common toxicities leading to the discontinuation of the first-generation BTK inhibitor ibrutinib. Typically, second-generation BTK inhibitors, such as acalabrutinib, are better tolerated than first-generation BTK inhibitors due to their increased selectivity resulting in fewer off-target effects such as cutaneous toxicities. There are few reports in the literature of acalabrutinib-induced purpura and only one report with the distribution of purpura limited to bilateral upper extremities. Awareness and timely identification and management of dermatologic adverse events induced by BTK inhibitors are increasingly important as the use of these medications increases. Developing appropriate management of cutaneous toxicities such as purpura due to acalabrutinib, and other BTK inhibitors, is important in order to maintain proper dose intensity and limit the need for discontinuation of these otherwise effective treatments.