Sorry to hear about your wife's suffering.
Also called Scalp Dysesthesia, Burning Scalp Syndrome is a treatment resistant skin condition like the notorious post herpetic neuralgia. Until recently this problem was not officially identified by dermatologists and had been put down to nervousness.
The exact cause of burning scalp syndrome is unknown. The following hypotheses are still unproven:
In your wife's case, # XXXXX & 4 may be playing a combined role in sustaining the condition.
The following should help your wife:
The following links could further give useful tips:
Hope my suggestions help your wife. Do let me know the results.
Please do give a feedback if you found this answer useful and informative. :)