09 July 2020
Compensating for lack of nerves cells
Published online 15 December 2009
There have been individual and rare reports of people who have a near complete insensitivity to pain. Most of these cases were diagnosed as hereditary sensory and autonomic neuropathy type IV (HSAN IV). However, two subjects have been diagnosed with the previously unknown condition of congenital absence of pain with hyperhidrosis (CAPH).
Although the two patients had nearly no sensitivity to pain and temperature, they showed no motor deficit. Contrary to individuals with HSAN IV, they both exhibited hyperhidrosis (that is, excessive sweating). One CAPH subject tested was found to have no cutaneous nerves, although the patient did have normal types of innervation to the sweat glands and blood vessels.
The researchers suggest that environmental or genetic factors might be responsible for the development of nerves to the sweat glands and blood vessels, independent from cutaneous innervations. Both subjects maintained some sensitivity to cutaneous stimulation, albeit greatly reduced. This suggests that vascular nerves have the ability to contribute to cutaneous perception.