The same varicella-zoster virus that causes chickenpox also causes shingles, which involves only a segment of the skin. Shingles is the popular term, in medical circles this condition is known as herpes zoster.
In a child with no antibodies to the chickenpox virus the virus travels to the whole skin surface causing the typical chickenpox lesions all over the body. In an adult who had prior exposure to the varicella-zoster virus there is a latent infection in the dorsal root ganglia of the spinal cord.
It remains confined to these cells until there is a change of the immune status. Factors such as stress weakening the immune system (often in college or university students) or a weakened immune system due to AIDS or due to immunosuppression (in transplant patients or patients who had chemotherapy for cancer) can allow the varicella-zoster virus to migrate along the nerve fibers to the associated skin segment. It is there where the disease breaks out and affects one dermatome on one side of the body. This is called “shingles” in common language or “herpes zoster” in the medical language.
Usually there is a prodromal stage where there is shooting pain in the skin dermatome, which will be breaking out later in the shingles rash. The pain period usually lasts about 2 or 3 days. Then redness of the skin appears from the inflammation of the virus. There is hypersensitivity to touch in the affected dermatome and multiple skin blisters (vesicles) appear in the same region. Most commonly it is in the skin of the lumbar and thoracic region that is affected and the rash is confined to one side.
Typically, the rash lasts for about 4 to 5 days. Most often the patients get herpes zoster only once, only less than 4% of patients might get a recurrence of it. However, these patients warrant a thorough workup for cancer that might be hidden, but weaken the immune system. Here is a link to a picture of shingles (thanks to www.vaccineinformation.org for this image).
There are two special cases that warrant mentioning:
A) In ophthalmic herpes zoster (=herpes zoster ophthalmicus) one of the facial branches (ophthalmic, maxillary or mandibular branch of the trigeminal nerve) is affected. If the ophthalmic branch is affected the varicella-zoster virus will often affect the cornea and there is a danger of corneal perforation. An emergency assessment and treatment by an ophthalmologist is required to abort the disease.
B) Ramsey Hunt’s syndrome or herpes zoster oticus is due to invasion of the varicella-zoster virus of the 8th cranial nerve and a ganglion of the facial nerve. This causes severe pain in the ear, dizziness (vertigo), hearing loss and palsy of the affected facial nerve. Herpes zoster vesicles can be seen in the ear canal. Two thirds of the tongue towards the tip of the tongue can experience a loss of taste. Signs of mild meningitis and encephalitis and involvement of other cranial nerves can be found associated with this.
Diagnosis and prognosis
The diagnosis is mostly made clinically although in occasional cases special blood tests (ELISA titer) might have to be done to confirm the diagnosis.
This involves that blood for serum is drawn early into the disease and at the time of complete recovery. A rise of specific antibodies detected this way will confirm the diagnosis.
Most of the time the prognosis is good meaning that the patient recovers without any consequences. However, with ophthalmic herpes zoster not infrequently postherpetic neuralgia develops, which is a painful condition in the affected dermatome with chronic pain and exaggerated skin hypersensitivity. With herpes zoster oticus loss of taste of the front 2/3 of the tongue could stay permanent, as can the loss of hearing on the affected side.
There has been a breakthrough with the introduction of acyclovir (brand name: Zovirax) with respect to the recovery time from shingles as well as with respect to the recovery from chickenpox.
Often the overall time of disease is cut in half and complications such as postherpetic neuralgia or bacterial superinfection are diminished significantly. Similarly, the other newer agents such as valacyclovir (brand name: Valtrex) and famciclovir (brand name: Famvir) are equally effective.
Ophthalmic herpes zoster
As mentioned above treatment of ophthalmic herpes zoster should be supervised by an ophthalmologist. Frequent examinations with a slit lamp and topical applications of antiviral eye drops in combination with oral antiviral therapy are essential. If the eye-specialist sees keratitis (involvement of the cornea of the eye) treatment with topical corticosteroid eye drops would be given. This is quite different from herpes simplex keratitis, where topical corticosteroids are contraindicated for fear of perforation of the cornea.
Herpes zoster oticus
Treatment of herpes zoster oticus should be supervised by an ENT specialist, although there are not too many options for effective treatment. High doses of oral prednisone are given as early as possible to control inflammation. Antiviral antibiotics are also administered to shorten the overall duration of the disease. However, no evidence is available to show reliably that hearing loss or loss of tongue sensitivity would be improved by these therapeutic measures. Decompression surgery to free the sensory branch of the facial nerve sometimes improves facial paralysis. Dizziness is treated symptomatically with diazepam, pain is treated with codeine or other narcotics.
Aids and herpes zoster
In AIDS patients who developed herpes zoster ongoing antiviral suppression therapy must be considered as otherwise herpes zoster would reoccur repeatedly.
1.The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 265.
2.James Chin et al., Editors: Control of Communicable Diseases Manual, 17th edition, 2000, American Public Health Association
3.The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 112.
4. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 115.
5. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 113.
6. Suzanne Somers: “Breakthrough” Eight Steps to Wellness– Life-altering Secrets from Today’s Cutting-edge Doctors”, Crown Publishers, 2008