An itchy vesiculobullous eruption in a patient with chronic lymphocytic leukaemia

Exaggerated reactions to insect bites are characteristic of patients with haemoproliferative disorders, particularly chronic lymphocytic leukaemia (CLL). Skin lesions usually appear after the diagnosis of leukaemia and seem unrelated to laboratory findings, disease course or therapy. Rarely, the eruption may precede the diagnosis of the haematologic malignancy. The patients usually do not recall of insect bites, and the diagnosis may require histological and laboratory investigations to exclude specific lesions or autoimmune bullous diseases. Lesions may run a chronic course and represent a therapeutic challenge. Here, we report an adult patient with CLL who developed itchy recurrent papulovesicular and bullous lesions. Differential diagnosis was made with cutaneous specific lesions of CLL, bullous pemphigoid and pemphigus vulgaris, but laboratory and histological investigations confirmed the diagnosis of an insect bite reaction. The patient was treated with oral H1 anti-histamines and topical corticosteroids under occlusion, with marked improvement after 10 days.