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Allied Journal of Medical Research
|
Volume 2
Page 33
allied
academies
CANCER THERAPY AND ONCOLOGY
NEUROLOGY AND BRAIN DISORDERS
&
International Conference on
International Conference on
J u n e 2 1 - 2 2 , 2 0 1 8 | O s a k a , J a p a n
Joint Event on
ITCH-SCRATCH CYCLE IS A CHRONIC
COGNITIVE ADDICTIVE BEHAVIOUR IN
OUR MIND
Chan Kam Tim Michael
Hong Kong Academy of Medicine, Hong Kong
S
cratching is a distinguishing feature of many resistant dermatosis like
chronic atopic dermatitis. Recently, discovery in neuroendocrinology,
immunology and MRI studies suggest itch – scratch cycle may be an
addictive neuroendocrine mediated pathological movement pathway
with an aberrant and imbalance of neurotransmitters in Central Nervous
system (CNS). Mas-related G protein-coupled receptor A3 (MrgprA3)
and MrgprC11 expressed afferent neurons penetrated in the epidermis
together with Transient Receptor Potential (TRP) receptors like TRPV
(vanilloid) 1, TRPV 3, TRPV4, TRPA (ankyrin) 1 together with Serotonin
receptors relay itch signals from the periphery synapses to the dorsal horn
of spinal cord. Pruritogenic signals via the afferent neurones synapse
with gastrin -releasing peptide receptors(GRPR) in the spinal cord.
GRPR activation released substance P, Calcitonin G Releasing Peptide,
Vasoactive Intestinal Peptide including Pituitary adenylate cyclase
activating peptides which was distributed in the CNS. Endothelin-1,
tachykinin through neurogenic inflammation increased levels of Th2
cytokines and interleukin – 31 also mediate itch. The central station of
itch transmission in our brain is the Thalamus. Hedonic scratch activated
the primary somatosensory S1 areas gave the perception of comfort in
the cingulate cortex decided the planned motor response of scratching.
The midbrain, striatum, ventral tegmental area, caudate nucleus and
ventromedial prefrontal cortex as shown by MRI studies are activated
in this pleasant circuitry. If this endogenous neuroendocrine circuitry
become uncontrolled; harmful cravings behaviour superseded. Insula
cortex and Claustrum of the brain play a prominent role in interoception
including addiction. They are highly activated when itch is intensified.
The adverse pruritic experience is represented in amygdala, subcallosal
gray matter and nucleus accumbens. The miswiring and imbalance of
5 Hydroxytryptamine and its multiple receptors are involved.Besides
pharmacological intervention, cognitive behavioural therapy including
education, refocusing attention strategy; virtual reality immersion; audio
visual distraction techniques; habit reversal training; arousal reduction
and cognitive restructuring are helpful.
Chan Kam Tim Michael is a practicing private
Dermatologist in Hong Kong. He received Der-
matology Specialist Fellowship in Hong Kong
Academy of Medicine in 1998. In the same year,
he was granted a Government of Hong Kong
scholarship for post graduate training in UCLA,
USA. He is now the Vice President of the Associ-
ation of Integrative Aesthetic Medicine in Hong
Kong. He was editor of the Hong Kong Journal
of Dermatology and Venerology from 2002 to
2007. He acts as Editorial Board Members of
the following international journals since 2017:
Research Journal of Nervous System; The Cog-
nitive Neuroscience Journal, Medical Reports
and Case Studies and Advances in Neurology
and Neuroscience. He has been working in the
University of Hong Kong as Honorary Clinical
Assistant Professor from 2007 to 2009. He is
now a part time lecturer in the Baptist Universi-
ty of Hong Kong for teaching Master Course in
Public Health.
pioneerskin@ymail.comBIOGRAPHY
Chan Kam Tim Michael, Allied J Med Res 2018, Volume 2