Of the 16 patients studied, 69% were females with an average age at diagnosis of 14 years. The mean duration of symptoms prior to diagnosis was 3.3 years. All patients had a chronic course, with 56% having a non-length dependent presentation. The chief complaint was sensory symptoms in 81% and autonomic symptoms in 19% of patients. Overall, symptoms of autonomic involvement, including lightheadedness, dry eyes, dry mouth, hyper, or hypohidrosis were seen in 75% of patients. Of those studied, 25% had Postural Orthostatic Tachycardia Syndrome (POTS) on the autonomic testing.  

All 16 patients were clinically diagnosed with SFN based on history and examination. Nerve conduction studies were performed in 75% of patients and were normal. 81% of patients had a skin biopsy, which was abnormal in all cases. 

Diagnostic workup showed immune-mediated causes in 56% of patients and 37.5% of patients had elevated IgM autoantibodies against trisulfated disaccharide IdoA2S-GlcNS-6s (TS-HDS) antigen. The range of TS- HDS antibody in our patient population was 11,000- 26,000, with normal values being less than 10,000. Concurrent EBV infection was found in 44% and oral HSV infection in 19%. Other causes included metabolic syndrome, diabetes, and HPV vaccination, among others.