Hyperalgesia in outpatients with dermal injury: quantitative sensory testing versus a novel simple technique.
OBJECTIVE
Dermal inflammation from many causes may produce a reversible period of hyperalgesia (increased sensitivity to pain perception) or allodynia (pain from innocuous stimuli). Hyperalgesia and allodynia have received relatively little attention in clinical trials of acute pain. We sought to quantitate tactile allodynia and thermal hyperalgesia in outpatients presenting with acute dermal injuries.


METHODS
We performed a randomized clinical trial to compare standard methodology for the assessment of hyperalgesia with two novel simple quantitative techniques.


METHODS
After Institutional Review Board approval, 40 patients presenting with acute chemical, thermal, mechanical, or infectious skin injury were subjected to a series of tests at the site of injury, an intact mirror site, and a noninjured ipsilateral control site.


METHODS
Quantitative thermal sensory testing (Medoc sensory analyzer) was followed by a 5-second application, in random order, of copper rods preheated in water to 40 degrees C, 43 degrees C, 46 degrees C, and 49 degrees C. Pressure testing was conducted with a 1.25-inch diameter commercially available pressure transducer gauge.


RESULTS
The observed pattern of responses was remarkably consistent among testing methods. All challenges with the four different temperatures elicited pain scores on a visual analog scale markedly greater at the injured than at the mirror or control site (P < 0.001 vs control). Pressure discomfort thresholds followed a similar pattern.


CONCLUSIONS
We conclude that hyperalgesia is a prominent contributor to discomfort in acute dermal injury and hence is a legitimate therapeutic target. Quantitation of the contribution of thermal hyperalgesia and tactile allodynia and assessment of their management is feasible using simple, rugged, low-cost methods. This inexpensive methodology may be useful in everyday clinical practice as well as in clinical research evaluating pharmacological agents to manage hyperalgesia.
Wright
Curtis
C
Adolor Corporation, Malvern, Pennsylvania, USA.
Goudas
Leonidas C
LC
Bentch
Abigail
A
Mehdi
Mohammad
M
Perry
Pamela P
PP
Carr
Daniel B
DB
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D010147:Pain Measurement / Q000379:methods; D010812:Physical Stimulation; D011312:Pressure; D012867:Skin / Q000293:injuries*; D013696:Temperature