Temperature modulated histamine-itch in lesional and nonlesional skin in atopic eczema - a combined psychophysical and neuroimaging study

Itch is the major symptom of many allergic diseases; yet it is still difficult to measure objectively. The aim of this study was to use an evaluated itch stimulus model in lesional (LS) and nonlesional (NLS) atopic eczema (AE) skin and to characterize cerebral responses using functional magnetic res...

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Bibliographic Details
Published in:	Allergy (Copenhagen) Vol. 65; no. 1; pp. 84 - 94
Main Authors:	Pfab, F, Valet, M, Sprenger, T, Huss-Marp, J, Athanasiadis, G.I, Baurecht, H.J, Konstantinow, A, Zimmer, C, Behrendt, H, Ring, J, Tölle, T.R, Darsow, U
Format:	Journal Article
Language:	English
Published:	Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-01-2010 Blackwell Publishing Ltd Blackwell
Subjects:	Adult Allergic diseases atopic dermatitis atopic eczema Biological and medical sciences Brain Brain Mapping Cerebral Cortex - physiology cerebral itch processing Child Dermatitis, Atopic - physiopathology Dermatology Eczema functional magnetic resonance imaging Fundamental and applied biological sciences. Psychology Fundamental immunology Histamine Histamine - pharmacology Humans Immunopathology Itch lesional skin Magnetic Resonance Imaging Medical imaging Medical sciences Perception - physiology Pruritus - chemically induced Pruritus - physiopathology Psychological aspects Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis Skin - drug effects Skin - innervation Skin - physiopathology Skin allergic diseases. Stinging insect allergies Temperature Allergy Immunopathology Skin disease Temperature lesional skin Dermatology Central nervous system Nervous system Pruritus Nuclear magnetic resonance imaging atopic eczema Atopy Encephalon Histamine Itch Immunology Atopic dermatitis cerebral itch processing Eczema Medical imagery Skin functional magnetic resonance imaging Functional imaging
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Summary:	Itch is the major symptom of many allergic diseases; yet it is still difficult to measure objectively. The aim of this study was to use an evaluated itch stimulus model in lesional (LS) and nonlesional (NLS) atopic eczema (AE) skin and to characterize cerebral responses using functional magnetic resonance imaging (fMRI). Thermal modulation was performed on a histamine stimulus in randomized order on LS or NLS in rapid alternating order from 32°C (warm) to 25°C (cold). Subjective itch ratings were recorded. Additionally, fMRI measurements were used to analyze the cerebral processing (n = 13). Healthy skin (HS) of age-matched volunteers served as control (n = 9). Mean VAS itch intensity was significantly (P < 0.0001) higher during the relative cold [55.2 ± 8.3% (LS); 48.6 ± 8.2% (NLS)] compared to the relative warm blocks [36.0 ± 7.3% (LS); 33.7 ± 7.6% (NLS)]. Compared to HS, the itch response was delayed in LS and NLS. Itch intensity was perceived highest in LS, followed by NLS and HS. For NLS, fMRI revealed at the beginning of the itch provocation a cerebral deactivation pattern in itch processing structures (thalamus, prefrontal, cingulate, insular, somatosensory and motor cortex). During the course of stimulation, the cerebral deactivation was reduced with time and instead an activation of the basal ganglia occurred. In contrast LS showed an activation instead of deactivation pattern already at the beginning of the stimulation in the above mentioned structures. Moderate short-term temperature modulation led to a reproducible, significant enhancement of histamine-induced itch with the strongest effect in LS. The differences in itch perception and itch kinetics between healthy volunteers and NLS in patients point towards an ongoing central inhibitory activity patients with AE, especially at the beginning of the itch provocation.
Bibliography:	http://dx.doi.org/10.1111/j.1398-9995.2009.02163.x These authors contributed equally to this work. Edited by: Thomas Bieber ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-News-1 ObjectType-Feature-3
ISSN:	0105-4538 1398-9995
DOI:	10.1111/j.1398-9995.2009.02163.x