Small-fibre neuropathy in female Fabry patients: reduced allodynia and skin blood flow after topical capsaicin

Fabry disease is a rare X-linked lysosomal storage disorder. The mutations result in a deficiency of the lysosomal enzyme alpha-galactosidase A causing accumulation of glycosphingolipids in the vascular endothelial cells and many other tissues. Given the X-linked inheritance, male patients are severely affected. Recently, attention has been drawn to female patients whether they also show signs of nerve involvement. An early sign of the disease is painful small-fibre neuropathy. The aim of this study was to evaluate a small-fibre dysfunction in female Fabry patients by using capsaicin applied topically. The response to capsaicin was evaluated by laser Doppler imaging. We found that the female Fabry patients had a significantly smaller increase in blood flow (p = 0.0003) after capsaicin application. The area of static mechanical allodynia and dynamic mechanical hyperalgesia was also significantly smaller (p = 0.006) in female Fabry patients. This indicates that female Fabry patients have a significant loss of small-fibre function and demonstrates that it is possible to evaluate this by a non-invasive method.