In '96 I was in a car accident that involved the truck I was in and a group of trees. I sustained quite a few injuries (none of which were very serious) including damage (read: bruises) to my right leg. The entire front of my leg, from my knee to my ankle, was covered in bruises. I have no feeling in most of my leg and haven’t since about 2 weeks after the accident. I can walk fine and I’m sure if I were burned badly I’d feel it. When I rub it though, I don’t feel it. There’s an area under my knee and just to the left of it that itches almost constantly. I used to scratch it to the point of bleeding. Now I just leave it alone. So I always thought that the reason I can’t feel a good part of my leg is because of nerve damage. But, if it really was nerve damage, would it still itch? Or is it because of something other than nerve damage?
Y’know, at this point I’d be seeing a doctor. I’d say it was nerve damage that caused both the numbness (not enough functioning nerve endings to pick up sensations) and the itching (some kind of overstimulation of the nerves in that region, possibly analogous to the ‘pins-and-needles’ common to those who have legs that fall asleep on them). Since you can still walk, I’d blame the bruises for doing the damage to subcutical sensory nerves. But I’m not a doctor. You should see one.
You know, I’m just a med student, so take this with a grain of salt…
That sounds like nerve damage. The bruising and the numbness are (probably) unrelated (besides being caused by the same crash). There are a group of several nerves which run down from the spine into the sciatic nerve and then split off into individual nerves in the lower thigh/knee area.
A neurologist will do a series of tests to determine exactly which nerve is damaged. This will be done by charting the exact area of numbness using several sensory modes – a toothpick for gentle pricking, a tuning fork for vibration, or a cotton swab for light touch. There are several possibilities : one nerve is damaged (neuropathy), several are damager (polyneuropathy), or the roots coming out of the spine are damaged (radiculopathy).
A good exam should reveal which one. Often, if the nerve is damaged, it will regrow slowly (about 1 cm a year if I remember well). Sometimes, damage is too great for regrowth. Only time (and a good neurologist) can tell.
I am away from my reference books right now. I am doing MD/PhD and I haven’t touched neuro for more than a year, so any help from other Teeming Millions would be appreciated. If I’ve made any glaring errors, I’ll post back when I get home.
Forget that, sex helps. A lot. If you want any help, let me know.
::runs away from a hail of thrown stones::
Thanks, Derleth. I suppose it would have made more sense for me to go right away or even the same year, but I just blew it off. Also, it’s gotten a lot more persistant and annoying lately.
Edwino, thank you. That was very informative. I never thought that I would have to see a neurologist though.
Surgoshan, thanks. I’ll keep that in mind. 
Ehh. I’m not sure I’d worry about it all that much.
When I was 17 my right foot got stomped on by a cow. HARD. She kinda slipped and went off-balance and used my foot to gain traction. Nothing broken, but the top of my foot looked like someone had stuffed a baseball under the skin for a few days.
I was relating this story at a party on 3 July when I realized that I again had feeling in that part of my foot, some 12 years later.
In regards to the itching :
Two possibilities as I see it –
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There is partial regrowth or partial survival of some of the nerves. You know how when your foot falls asleep the first feeling to come back is prickly “pins-and-needles?” “Falling asleep” is actually a nerve palsy where pressure messes up nerve conduction. Different nerves have different responses, and therefore respond differently (and survive insult differently). Pain/itch nerves tend to do pretty well (unfortunately) as they are small and there are lots of them.
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It may be akin to “phantom limb” feelings. When feeling is lost in a limb (or a limb is amputated), the brain and spinal cord have to reassign the neurons that dealt with the area (like when you go blind, your hearing gets better – same concept). This is done in a haphazard, wacky way. Often time when perception and sensation don’t match, the brain tends to put pain perceptions down (like phantom limbs). Unfortunately, this pain/itch is not responsive to any type of drug except I think antidepressants (as it is “cortical pain” – pain perceived by the brain outside of the pain transmission system).
I don’t know if a neurologist can help, especially 4 years post incident. He can surely diagnose and perhaps give you an idea of what the future holds for that area of leg. Nothing speeds up nerve growth or replaces lost nerves (except nerve grafts, and these nerves are often the donor nerves for grafts).