Atopic eczema and histamine-induced sensations.

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.