Itch – one bothersome symptom of rosacea dermatitits. Advances in
understanding the causes of skin itch and treating it.

Geoffrey
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Dr. Geoffrey Nase
Ph.D. Microvascular Physiologist
http://www.drnase.com
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Am J Clin Dermatol. 2003;4(9):617-22.


Itch associated with skin disease: advances in pathophysiology and
emerging therapies.

Yosipovitch G, Fleischer A.

Itch, also known as pruritus, is the major symptom in skin diseases
with a variety of etiologies and pathophysiologies. Significant
progress has been achieved in understanding the pathophysiology of
itch in the last 5 years. Neurophysiological experiments in humans
and animals have revealed that itch is carried by specific C nerve
fibers. Recent studies have demonstrated that peripheral mediators
other than histamine are involved in induction of itch. Mast cell
tryptase seems to be an important mediator in itch by its activation
of proteinase activated receptor 2 in the sensory nerves. Opioids
have central and peripheral itch producing activity. Neuropeptides,
such as substance P, induce itch by their effect on mast cells.
Based upon our improved understanding of the neurophysiology of itch
a clinical classification of itch has been proposed. The
classification highlights differences between peripheral
pruritoceptive itch, neuropathic itch (itch related to damage to
afferent nerve fibers) and neurogenic itch (itch originating in the
central nervous system without any evidence of nerve damage).
Emerging therapies based on these findings include topical vanilloid
receptor antagonists, topical antihistamines, and topical
arachidonic acid inhibitors, as well as inhibitors of non-histamine
inflammatory mediators, immunomodulators and strontium salts.
Systemic therapies include thalidomide, opioid antagonists,
phototherapy with narrow band UVB and experimental treatments with
cutaneous field stimulation and vagal nerve stimulation.With the new
information it seems we will be able to better help our dermatologic
patients who have itch, however we are not closer to identifying a
single agent specifically targetable to this symptom.

Publication Types:
• Review