title: Intracutaneous histamine injection can detect damage of cutaneous afferent fibres in postherpetic neuralgia.
abstract: BACKGROUND
  The axon reflex response in diseased skin of patients with postherpetic neuralgia may be significantly impaired.
  
  
  OBJECTIVE
  In the present study we introduced a simple test for quantifying the decreased axon reflex flare response in the clinical routine.
  
  
  METHODS
  Histamine was intradermally applied to the diseased dermatome as well as to the corresponding dermatome of the contralateral side of the body. Ten minutes after application, skin blood flow and the extension of the hyperaemic response were assessed by means of laser Doppler scanning.
  
  
  RESULTS
  In the skin region affected by the postherpetic neuralgia, the hyperaemic area was significantly smaller than in the healthy skin. The mean flux values did not differ significantly between the two sites. There was no correlation between the hyperaemic response and the intensity of pain sensation assessed by a clinical visual analogue score.
  
  
  CONCLUSIONS
  The smaller hyperaemic area in the dermatome with postherpetic neuralgia strongly indicates a C fibre or C nociceptor damage. We consider histamine injections as a useful tool in the differential diagnosis of postherpetic neuralgia.
authors.affiliation: Department of Dermatology, Ruhr University, Bochum, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Stücker
authors.forename: P
authors.initials: P
authors.lastname: Hügler
authors.forename: G
authors.initials: G
authors.lastname: von Kobyletzki
authors.forename: T
authors.initials: T
authors.lastname: Reuther
authors.forename: K
authors.initials: K
authors.lastname: Hoffmann
authors.forename: H
authors.initials: H
authors.lastname: Laubenthal
authors.forename: P
authors.initials: P
authors.lastname: Altmeyer
mesh_terms: D000368:Aged; D001369:Axons / Q000502:physiology; D003937:Diagnosis, Differential; D005260:Female; D006562:Herpes Zoster / Q000150:complications* / Q000503:physiopathology; D006632:Histamine / Q000008:administration & dosage; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D007271:Injections, Intradermal; D017078:Laser-Doppler Flowmetry; D008297:Male; D009412:Nerve Fibers / Q000502:physiology*; D009437:Neuralgia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D009475:Neurons, Afferent / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000008:administration & dosage; D009619:Nociceptors / Q000502:physiology; D010147:Pain Measurement; D012018:Reflex / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply / Q000294:innervation*; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D018377:Neurotransmitter Agents; D014665:Vasodilator Agents; D006632:Histamine