Pathophysiology of Shingles.

* I am still trying to find more, but the info overlaps! :( *
* Will merge with Shakir's when he pass his info to me. :) *

· Caused by the varicella zoster virus.
· After an infection of chicken pox, the virus lies dormant in the dorsal root ganglion and if it reactivates, it would cause shingles.
· The rash is made up of tiny blister-like spots that hold fluid. Shingles occurs because of a reactivation of the chickenpox virus, which remains in the nerve cells of the body after an attack of chickenpox.
· How exactly it reactivates is not known, but it was found that the cell-specific-VZV immunity decreases with age, making a person more prone to reactivating the virus.
· The virus causes imflammation at the dorsal root ganglia and haemorrhagic necrosis of nerve cells .
· Shingles is a painful, unilateral rash, that is usually restricted to a dermatomal distribution.
· It usually appears as band of blisters that wraps from the middle of the back around one side of the chest to the breastbone, and can affect the face.
· It is usually benign. But may have complications.
· Clinical features of herpes zoster may follow a progression through 3 stages, prodromal, acute, and chronic.
o The prodromal and acute phases seldom require more than symptomatic management.
o The chronic pain syndrome, postherpetic neuralgia (PHN), demands a more aggressive approach - localized pain persisting for at least 3 months after the acute inflammatory phase of zoster in the skin. The symptoms may include severe pain or sensations of burning or itching and may continue for years and the frequency and intractability of PHN increases with age
· Tender, painful skin signals the beginning of an attack.
· The skin then turns red and breaks out in blisters.
· The rash can last for a few days or weeks.
· During that time, a scaly crust might appear. Once the attack is over, the skin usually returns to normal but there can be some scarring in severe cases




References :
http://www.medscape.com/article/788310-overview
http://www.ncbi.nlm.nih.gov/pubmed/3287356
http://www.mayoclinic.com/health/shingles/DS00098
http://www.health.gov.au/internet/main/Publishing.nsf/Content/cda-pubs-cdi-2002-cdi2604-htm-cdi2604o.htm
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Shingles?open