Q: Today I was doing some shopping which is not something I get to do very often. I noticed that my left leg felt numb (my outer thigh ) what would cause
something like that ? It is not numb now.... I have primary sjogrens if that
helps... also I had my purse strap across my chest like one would do a messenger bag....I have had am emg and a nerve conduction study both were normal... I have been having burning sensations all over my body and numbness in spots....
A: May be neuralgia paresthetica (meralgia paresthetica), involving the pure sensory lateral femoral cutaneous nerve. This nerve originates in the lumbar spine and travels around the pelvis, behind the inguinal ligament to the thigh. The nerve may be compressed in the groin area by tight jeans,(it has been named the Calvin Klien Sndrome), by tight underwear, sitting, and/or adipose (fat) tissue. Perhaps hip hugging jeans and belts could compress the nerve iliac spine (pelvic bone). Result is numbness, burning, tingling of the lateral thigh (sometimes groin, buttocks, rib cage). Sometimes the area is hypersensitive to light touch or to heat (warm shower causes "burning"). The fact that the symptom resolved does support the compressive possibility.
No reports of NP and Sjs were found (Pub Med, MD Consult, Up-to-Date, Google searches). However, there is reference to NP being associated with diabetes and thyroid disease.
It is theorectically possible that having Primary Sjs, which is commonly associated with peripheral neuropathies, could increase the risk of developing NP in addition to other neuropathies. The fact that you describe other neuropathic syptoms (burning and numbness) in other areas possibly could increase the risk of symptoms from a nerve compression; however we are not aware of published data to support/dispute this).
Wikipedia Encyclopedia has a good description of NP/meralgia paraesthetica.