BACKGROUND: In previous studies we observed diminished pruritogenic effects and reduced flare reactions after iontophoretic application of histamine in patients with acute atopic eczema (AE). OBJECTIVE: To determine a possible mechanism acting on peripheral and central nervous components of the histamine-mediated itch reaction. METHODS: Forty-eight individuals with different predispositions to AE were included. According to an 'atopic score', 16 individuals had no history of atopic symptoms, another group of 16 individuals showed a disposition to AE and a further group of 16 individuals had a clear history of AE. However, all individuals were devoid of acute atopic symptoms and their IgE levels were below 150 U/ml. Histamine was iontophoretically applied to the skin of the forearm, and stimulus-induced itching and burning sensations were rated on visual analogue scales. RESULTS: Individuals with previous episodes of AE reported weaker itch sensations after histamine. In addition, the sensations were often described as burning by this group. CONCLUSION: The results suggest an altered central nervous responsiveness already in symptom-free individuals, since peripheral vascular reactions to histamine were not significantly reduced.
BACKGROUND: In previous studies we observed diminished pruritogenic effects and reduced flare reactions after iontophoretic application of histamine in patients with acute atopic eczema (AE). OBJECTIVE: To determine a possible mechanism acting on peripheral and central nervous components of the histamine-mediated itch reaction. METHODS: Forty-eight individuals with different predispositions to AE were included. According to an 'atopic score', 16 individuals had no history of atopic symptoms, another group of 16 individuals showed a disposition to AE and a further group of 16 individuals had a clear history of AE. However, all individuals were devoid of acute atopic symptoms and their IgE levels were below 150 U/ml. Histamine was iontophoretically applied to the skin of the forearm, and stimulus-induced itching and burning sensations were rated on visual analogue scales. RESULTS: Individuals with previous episodes of AE reported weaker itch sensations after histamine. In addition, the sensations were often described as burning by this group. CONCLUSION: The results suggest an altered central nervous responsiveness already in symptom-free individuals, since peripheral vascular reactions to histamine were not significantly reduced.