ORIGINAL ARTICLE Insect-bite-like reaction in patients with chronic lymphocytic leukemia: a study from the Israeli Chronic Lymphocytic Leukemia Study Group Osnat Bairey 1,2 *, Neta Goldschmidt 3,4 , Rosa Ruchlemer 5 , Tamar Tadmor 6,7 , Neomi Rahimi-Levene 2,8 , Mona Yuklea 9 , Lev Shvidel 4,10 , Alain Berrebi 4,10 , Aaron Polliack 3,4 , Yair Herishanu 2,11 , on behalf of the Israeli Chronic Lymphocytic Leukemia Study Group (ICLLSG) 1 Hematology Institute, Rabin Medical Center, Beilinson Hospital, Petach Tikva; 2 Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 3 Hematology Institute, Hadassah Medical Center, Jerusalem, Israel; 4 Faculty of Medicine, Hebrew University, Jerusalem, Israel; 5 Hematology Institute, Shaare Zedek Medical Center, Jerusalem, Israel; 6 Hematology Institute, Bnai-Zion Medical Center, Haifa, Israel; 7 Faculty of Medicine, Technion University, Haifa, Israel; 8 Blood Bank and Hematology Institute, Assaf Harofeh Medical Center, Zerifin, Israel; 9 Hematology Institute, Meir Medical Center, Kfar Saba, Israel; 10 Hematology Institute, Kaplan Medical Center, Rehovot, Israel; 11 Hematology Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Abstract An insect-bite-like reaction is known to occur in patients with chronic lymphocytic leukemia (CLL). Most of the literature, however, consists of isolated case reports or small case series. The aim of this retrospective study was to review the national experience with insect-bite-like reaction in a large group of patients with CLL. The study cohort of patients with these skin reactions consisted of 48 patients (25 males, 23 females) of mean age 64.8 yr (range 33–89) at skin eruption. Data on clinical, histologic, immunophenotypic, and cytogenetic characteristics, treatment, and outcome were collected from the medical files. Mean time between diagnosis of CLL and appearance of the skin lesions was 3.1 yr (range À4 to 14 yr). The eruption was not related to disease activity or the course of the hematological disease. The eruption preceded the diagnosis of CLL in 10 patients (by 0–4 yr); and followed the diagnosis in 36; in 11 patients, it occurred during therapy for CLL and in nine after therapy. Mean duration of the skin findings was 21.5 months (range 0.3–132). The eruption usually presented in summer, although it occurred also at other times of the year, and predominantly affected the upper and lower limbs, although it also appeared on unexposed areas. Treatment included local ointments, antihistaminics, oral steroids, antibiotics, phototherapy, and dapsone with varying responses. Insect-bite-like reactions is a relatively common and disturbing skin reaction in CLL patients, it may be related to the immune dysregulation accompanying CLL and further exacerbated by external factors, including actual insect bites, chemoimmunotherapy, and pyogenic infection. Key words chronic lymphocytic leukemia; insect-bite-like; skin lesions; pruritus *Correspondence Osnat Bairey, MD, Hematology Institute, Rabin Medical Center, Beilinson Hospital, Petach Tikva 49100, Israel. Tel: +972 3 937 7906; Fax: +972 3 937 8046; e-mail: obairey@post.tau.ac.il Accepted for publication 16 September 2012 doi:10.1111/ejh.12015 Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults in the western world. Leukemic cells typ- ically accumulate in bone marrow, lymph nodes, liver, and spleen, although any organ may be involved. The skin is one of the common extranodal sites infiltrated by CLL cells. Historically, skin lesions in patients with CLL have been classified into two major groups: specific (cutaneous involvement by leukemic cells), affecting 8.3% of patients, and paraneoplastic or non-specific (not leukemic), affecting up to 45% of patients (1). Specific cutaneous lesions are characterized histopathologically by diffuse dense dermal infiltrates of small lymphocytes with the aberrant CD19+/ © 2012 John Wiley & Sons A/S 491 European Journal of Haematology 89 (491–496)