The nerve conduction study usually provides useful information for making diagnosis. A CT scan is sometimes used to rule out some causes from the central nervous system.

Paresthesia or "persistent anesthesia" is a transient or potentially permanent condition of extended numbness after administration of local anesthesia and the injected anesthetic has terminated.

Potential causes include trauma induced to the nerve sheath during administration of the injection, hemorrhage about the sheath, type of anesthetic used, or administration of anesthetic potentially contaminated with alcohol or sterilizing solutions.

Fabry disease is suspected based on the individual's clinical presentation, and can be diagnosed by an enzyme assay (usually done on leukocytes) to measure the level of alpha-galactosidase activity. An enzyme assay is not reliable for the diagnosis of disease in females due to the random nature of X-inactivation. Molecular genetic analysis of the "GLA" gene is the most accurate method of diagnosis in females, particularly if the mutations have already been identified in male family members. Many disease-causing mutations have been noted. Kidney biopsy may also be suggestive of Fabry disease if excessive lipid buildup is noted. Pediatricians, as well as internists, commonly misdiagnose Fabry disease.

The first treatment for Fabry's disease was approved by the US FDA on April 24, 2003. Fabrazyme (agalsidase beta, or Alpha-galactosidase) was licensed to the Genzyme Corporation. It is an enzyme replacement therapy (ERT) designed to provide the enzyme the patient is missing as a result of a genetic malfunction. The drug is expensive — in 2012, Fabrazyme's annual cost was about US$200,000 per patient, which is unaffordable to many patients around the world without enough insurance. ERT is not a cure, but can allow improved metabolism and partially prevent disease progression, as well as potentially reverse some symptoms.

The pharmaceutical company Shire manufactures agalsidase alpha (which differs in the structure of its oligosaccharide side chains) under the brand name Replagal as a treatment for Fabry's disease, and was granted marketing approval in the EU in 2001. FDA approval was applied for the United States. However, Shire withdrew their application for approval in the United States in 2012, citing that the agency will require additional clinical trials before approval.

Clinically the two products are generally perceived to be similar in effectiveness. Both are available in Europe and in many other parts of the world, but treatment costs remain very high.

Besides these drugs, a gene therapy treatment is also available from the Canadian Institutes of Health. Other treatments (oral chaperone therapy -Amicus-, plant-based ERT -Protalix-, substrate reduction therapy -Sanofi-Genzyme-, bio-better ERT -Codexis-, gene editing solution -Sangamo- are currently being researched.

Pain associated with Fabry disease may be partially alleviated by ERT in some patients, but pain management regimens may also include analgesics, anticonvulsants, and nonsteroidal anti-inflammatory drugs, though the latter are usually best avoided in renal disease.