Cyclosporine, a member of the calcineurin inhibitor family, has immunomodulatory effects on T cells. It blocks the earliest stages of the immune response by binding to cyclophilin, thus inhibiting calcineurin. It was initially used for transplant patients to prevent transplant rejections. The main indication for cyclosporine in dermatology is severe psoriasis. Other dermatologic indications for the use of cyclosporine include atopic dermatitis, chronic idiopathic urticaria, pyoderma gangrenosum, and Behçet's disease.