Chronic inflammatory demyelinating polyneuropathy (CIDP) and multiple motor neuropathy (MMN) are immune mediated neuropathies with a heterogeneous clinical presentation. This makes both the diagnosis and choosing the right treatment strategy challenging. Furthermore, several trails suggest overtreatment in patients with long-term maintenance treatment in CIDP. The aim of this thesis was to identify some of the challenges in treatment and diagnosis of CIDP and MMN, and to explore induction treatment and possible overtreatment in CIDP. In the first part of this thesis, we identified patients who did not meet the mandatory diagnostic criteria but did respond to immunomodulatory treatment. Furthermore, we conducted a diagnostic test accuracy review on IgM anti-GM1 antibody testing and found the test characteristics to be of limited added value. In the second part of this thesis, we performed a literature review showing possible overtreatment with intravenous immunoglobulin (IVIg) maintenance treatment in CIDP patients. Furthermore, we performed a pilot study with combined IVIg en intravenous methylprednisolone as induction treatment showing more than half of the CIDP patients remained clinically stable at one-year follow up. In addition, we present a case series of patients with cutaneous lupus erythematosus as a side effect of long-term IVIg treatment. Finally, we performed a randomized controlled non-inferiority trial, in which we compared IVIg withdrawal with placebo with continuation of IVIg treatment in CIDP patients. We showed that a considerable part of the participants could stop treatment without experiencing deterioration and that IVIg withdrawal is safe.