Hand Surgery Source

Anhydrous of Skin Sign

Test, Exam and Signs

Historical Overview

  • Beginning in the 1950s, Erik Moberg documented the recovery of hand sensation in patients after nerve injury and repair.1 He invented the expression “tactile gnosis.” 2  

Description

  • Innervated skin, which usually displays wrinkling when immersed in warm water, sweats normally because of the intact sympathetic nerve fibers in peripheral nerves.1,3 
  • The anhydrous of skin test, finger wrinkling test, colorimetric sweating test or electrical skin resistance test can help determine if a patient has peripheral nerve injuries.1,4
  • After repair of peripheral nerve injuries, wrinkling and sweating of the skin should return from palm to tips.3 This recovery process will take ~5 years in adults and 2 years in children.5

Pathophysiology

  • The anhydrous of skin test can help to diagnose the sensory loss and sensory recovery related to a median or ulnar nerve injury.3

Instructions

1. Obtain an accurate and complete patient history, including any history of diabetes mellitus. Ask the patient to rate on a scale from 1 to 10, how much pain s/he usually experiences in the affected hand.

2. Assess the amount of moisture on the palm and fingers in the distribution of the injured and uninjured nerves.

3. Examine the contralateral hand.

Related Signs and Tests

  • Moberg’s ninhydrin sweat test
  • Weber’s two-point discrimination test 5
  • Range of motion (ROM) 4  
  • Tinel’s sign4

Diagnostic Performance Characteristics

  • Using the anhydrous of skin test in conjunction with other sympathetic nerve tests enhances reliability.
Presentation Photos and Related Diagrams
  • Anhydrous Skin on ulnar hand secondary to chronic ulnar nerve laceration
    Anhydrous Skin on ulnar hand secondary to chronic ulnar nerve laceration
Definition of Positive Result
  • A positive result occurs when the skin of the patient’s affected hand in the distribution of the injured nerve is drier than normal.
Definition of Negative Result
  • A negative result occurs when the skin of the patient’s affected hand in the distribution of the injured nerve is not drier than normal.  
Comments and Pearls
  • The anhydrous of skin tests are useful when examining young children, other patients who may not understand subjective tests or patients suspected of malingering. 1  
Diagnoses Associated with Tests, Exams and Signs
Video
Examining the skin for the dryness associated with denervation.
References
  1. Sunderland S. Testing sympathetic function. Nerves and Nerve Injuries. Edinburgh: Churchill Livingstone, 1978.
  2. Dellon AL. The sensational contributions of Erik Moberg. J Hand Surg Br 1990;15(1);14-24. PMID: 2407791
  3. O’Riain S. New and simple test of nerve function in hand. Br Med J 1973;3:615-6. PMID: 4755183
  4. Phelps PE, Walker E. Comparison of the finger wrinkling test results to established sensory tests in peripheral nerve injury. Am J Occup Ther 1977;31(9):565-72. PMID: 907018
  5. Stromberg WB, Mcfarlane RM, Bell JL, et al. Injury of the median and ulnar nerves: one hundred and fifty cases with an evaluation of Moberg’s ninhydrin test. J Bone and Joint Surgery 1961;43A:717-30.