Dermatological complications following initiation of lenalidomide in a patient with chronic lymphocytic leukaemia.

Off-label use of lenalidomide (Len) in chronic lymphocytic leukemia (CLL) is becoming increasingly frequent. When compared with thalidomide, Len has been reported to have more potent anti-tumour activity and a better safety profile. However, dermatological side-effects are known to occur with both drugs. Clinical trial design often precludes precise quantification of infrequent toxicities and studies frequently report only grade 3-4 toxicities without a detailed description of rashes, leading to under-recognition of these complications in the community. Careful long-term tracking of late adverse effects with prompt reporting on recognition is imperative while monitoring patients for potential adverse events as we enter the new era of targeted therapies. We present an unusual case of CLL that was complicated by erythema annulare centrifugum and neutrophilic dermatosis (Sweet's syndrome) after starting Len.