« Measles | Main | Urinary Tract Infection »
Shingles
Herpes zoster, colloquially known as shingles, is the reactivation of varicella zoster virus, leading to a crop of painful blisters over the area of a dermatome. It occurs very rarely in children and adults, but its incidence is high in the elderly, as well as in any age group of immunocompromised patients. Treatment is generally with acyclovir. Many develop a painful condition termed postherpetic neuralgia.
signs and symptoms of shingles
Often, the pain is the first shingles symptom. Then 2-3 crops of red lesions develop, which gradually turn into small blisters filled with serous fluid. With shingles, the symptoms of a feeling of unwellness often occurs.
As long as the blisters have not dried out, HZ patients may transmit the virus to others. This could lead to chickenpox in people (mainly young children) who are not yet immune for this virus.
Shingles blisters are unusual in that they only appear on one side of the body. That is because the chickenpox virus can remain dormant for decades, and does so inside the spinal column or a nerve fiber. If it reactivates as shingles, it affects only a single nerve fiber, or ganglion, which can radiate to only one side of the body. The blisters therefore only affect one area of the body and do not cross the midline. They are most common on the torso, but can also appear on the face (where they are potentially hazardous to vision) or other parts of the body.
diagnosis of shingles
The diagnosis is visual - very few other diseases mimic herpes zoster. In case of doubt, fluid from a blister may be analysed in a medical laboratory.
pathophysiology
The causative agent for herpes zoster is varicella zoster virus (VZV). Most people are infected with this virus as a child, as it causes chickenpox. The body eliminates the virus from the system, but it remains dormant in the ganglia adjacent to the spinal cord or the ganglion semilunare (ganglion Gasseri) in the cranial base.
Generally, the immune system suppresses reactivation of the virus. In the elderly, whose immune response generally tends to deteriorate, as well as in those patients whose immune system is being suppressed, this process fails. (Some researchers speculate that sunburn and other, unrelated stresses that can affect the immune system may also lead to viral reactivation.) The virus starts replicating in the nerve cells, and newly formed viruses are caried down the axons to the area of skin served by that ganglion (a dermatome). Here, the virus causes local inflammation in the skin, with the formation of blisters.
The pain characteristic of herpes zoster is thought to be due to irritation of the sensory nerve fibers in which the virus reproduces.
therapy for shingles
Aciclovir (an antiviral drug) inhibits replication of the viral DNA, and is used both as prophylaxis (e.g. in patients with AIDS) and as therapy for herpes zoster. Other antiviral are valaciclovir and famciclovir. Steroids are often given in severe cases.
The long term complication postherpetic neuralgia may cause persistent pain that lasts for years. Pain management is difficult as conventional analgesics may be ineffective. Alternative agents are often used, including tricyclic antidepressants, anticonvulsants, and/or topical agents.
shingles prognosis
The rash and pain usually subside within 3 to 5 weeks. Sometimes serious effects including partial facial paralysis (usually temporary), ear damage, or encephalitis may occur. Shingles on the upper half of the face (the first branch of the trigeminal nerve) may result in eye damage and require urgent ophthalmological assessment.
Since shingles is a reactivation of a virus contracted previously—often decades earlier—it cannot be induced by exposure to another person with shingles or chickenpox. However, those with active blisters can spread chickenpox to others who have never had that condition or who have not been vaccinated against it.
Posted by Staff at May 17, 2005 3:46 AM
blog comments powered by DisqusComments Archive
I've had blisters forming for 2 months that appear to be like chicken pox. They appear in different areas of my body (wrist, face, neck. Takes about 2 days, they itch, then crust over before they start to heal. I've used anifungals,cortizone creams, (almost everything I have in my medicine supply.) Is this what I have?
Posted by: kathy ohman at January 8, 2006 2:56 PM
My husband has bright red blotches on his right-side forehead and face and excrutiating pain that radiates from the top of his head to his right ear. He has a small cyst on the right side of the inside of his mouth. He also suffers from weakness particularly on his right side. Could this be a form of Shingles?
Posted by: Paula at June 12, 2006 4:19 AM
I think I might have shingles of Trigeminal nerve. Do I see a gp, neurologist, or opthamologist? Tingling of my forhead - raised red bumpy areas on my left temporal part of my forhead. Just started 9/16.
Posted by: Chris McLeod at September 17, 2006 10:10 PM
i have rashes on my croutch and groin, went to skin dr, and was told it is jock itch. tried all different creams and epson salt bathes, has not getting any better,i have had almost 6months , any idea what it is, it itches & burns,
Posted by: tony at December 16, 2006 5:58 PM
i have rashes on my croutch and groin, went to skin dr, and was told it is jock itch. tried all different creams and epson salt bathes, has not getting any better,i have had almost 6months , any idea what it is, it itches & burns,
Posted by: tony at December 16, 2006 5:58 PM
