To evaluate clinical characteristics of pediatric Small Fiber Neuropathy (SFN) in rheumatological disorders to create greater awareness about this disease among treating physicians.

Small Fiber Neuropathy (SFN) is a common but underdiagnosed neurologic complication which can be secondary to rheumatologic disorders. While well described in adults, there is limited data for the pediatric population.

Retrospective chart review was performed to identify patients. SFN was diagnosed by Epidermal Nerve Fiber Density (ENFD), values on skin biopsy, and/or Quantitative Sudomotor Axon Reflex Test (QSART) testing. Rheumatological disorders were diagnosed using published standard criteria for children.

Nine patients with SFN and coexisting rheumatologic disorders were identified. Seven patients were diagnosed with Sjogren’s syndrome, one with scleroderma, and one with both Sjogren’s syndrome and Systemic Lupus Erythematosus (SLE). Mean age at diagnosis of neuropathy and rheumatologic disorder was 15.55 years and 16.11 years, respectively. 57.1% of patients with Sjogren’s syndrome were diagnosed with neuropathy before their Sjogren’s diagnosis with a mean delay of 1.3 years. Presenting symptoms were neuropathic pain or sensory impairment, orthostatic dizziness, headaches, and constipation, but patients later developed a combination of these symptoms. Postural Orthostatic Tachycardia Syndrome (POTS) was diagnosed in 5 patients (55.6%). Comorbid conditions included Ehlers-Danlos syndrome (EDS), mast cell activation, Hashimoto’s thyroiditis, and Celiac disease. Five patients have started treatment: 4 with IVIG and 1 with Plaquenil for ≥ 3 months. Four of these patients have shown clinical improvement.  

Sjogren’s syndrome should be suspected in children with SFN as most patients were diagnosed with neuropathy before their rheumatologic diagnosis. Scleroderma and SLE can have associated SFN. Neuropathic pain and/or sensory impairment, GI symptoms, and/or orthostatic intolerance can be the presenting symptom. IVIG in conjunction with immunomodulatory therapy for rheumatologic disorders is an effective add-on treatment for SFN.