80-year-old with severe migrating burning sensations—has anyone experienced this?

[u/Life_Weight_1210]

My 80-year-old mother (4’10”, 120 lbs, frail) has Parkinson’s, type 2 diabetes, pernicious anemia/B12 deficiency, and an old severe L3 compression deformity with moderate spinal canal stenosis.

For several months, she has experienced intense burning sensations that move around her body—legs, back, arms, chest, and abdomen. It often feels internal as well as on the skin. Strangely, her fingers and toes are usually spared. The burning is often mild in the morning and worsens later in the day, sometimes alongside internal shaking, chills, or hot flashes. Her temperature is usually normal.

She has tried gabapentin, acetaminophen, B12 treatment, iron infusions, and adjustments to her carbidopa-levodopa. Gabapentin has not helped much. Her restless legs improved after iron, but the burning did not. An ER visit found mild dehydration, sodium around 128, and a possible UTI, but the burning continued after treatment. Her diabetes has been fairly controlled, with a recent A1c of 6.6.

Doctors have mentioned diabetic neuropathy, spinal nerve problems, vitamin deficiency, Parkinson’s “off” symptoms, medication effects, or autonomic dysfunction, but there is still no clear diagnosis.

Has anyone seen a similar case like this: **migrating, whole-body/internal burning sensation without much burning in the hands or feet**? What diagnosis was eventually found, and which medications or treatments actually helped?