Pruritus in neuromyelitis optica spectrum disorders and multiple sclerosis

Differential diagnosis between neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) at early stage remains challenging at present. Pruritus is reported as a common or specific feature in NMOSD with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). We aim to verify whether pruritus can help in distinguishing NMOSD from MS.

We retrospectively reviewed the medical records of consecutive cases of NMOSD and MS patients, demographic data, clinical features, whether or not had pruritus, serum AQP4-IgG status and magnetic resonance imaging (MRI) results.

21.0% (22/105) of NMOSD patients and 2.1% (2/96) of MS patients reported pruritus during disease course (p < 0.01). 20.5% (18/88) of AQP4-IgG positive and 23.5% (4/17) of AQP4-IgG negative NMOSD patients reported pruritus during disease course (p = 0.775). 12.4% (13/105) of NMOSD and 1.0% (1/96) of MS patients reported pruritus at the first attack episode of disease (p < 0.01). 20.0% (21/105) of NMOSD and 1.0% (1/96) of MS patients reported pruritus at the first and second attack episodes of disease (p < 0.01).

Pruritus is a common and relatively specific feature in either AQP4-IgG positive or negative NMOSD. Pruritus occurs more frequently in NMOSD than MS, which may help in distinguishing NMOSD from MS, especially at early stage.