Shingles
Also known as herpes zoster, varicella zoster
What is shingles?
Shingles is a localised, blistering, red and painful rash. It can involve the chest, neck, abdomen, face or ear canal and central nervous system.
What causes shingles?
Shingles is caused by the reactivation of the varicella virus, the same virus responsible for chicken pox. The virus can lie dormant in nerve cells once a person has contracted chicken pox and may be reactivated by stress, illness, immunosuppression, older age, trauma, radiotherapy and contact with another person with varicella or herpes zoster.
What does the shingles rash look like?
A person suffering from shingles may experience burning pain, stinging, itching or a change in sensation in affected skin. The person may have a fever and feel unwell.
These symptoms may precede the appearance of the rash which consists of redness of the skin followed by blisters. The rash is a unilateral band-like eruption involving dermatomes (one-sided sections of skin related to the nerve supply to that area) of the chest, neck abdomen or face. It commonly stops at the midline but can occasionally involve multiple dermatomes or become bilateral. The acute phase settles over a 3-week period. Then it is followed by crusting and healing, and sometimes scarring.
The oral cavity and ear canal can be affected in some cases.
What problems can occur with shingles?
- Post herpetic neuralgia is persisting pain in the area affected by the shingles that occurs after the acute rash has healed. This can persist for months or years and can be debilitating. The pain described can be a continuous or intermittent burning sensation and there may be a change in touch sensation, ie numbness or increased sensitivity. There may also be a persistent itch.
- Vision impairment from painful eye infections involving the ophthalmic nerve. This can cause scarring and ulceration of the cornea, impairment of visual acuity and secondary glaucoma.
- Hearing loss from the involvement of the nerve innervation to the ear and ear canal. This is condition is called Ramsay Hunt syndrome and results in earache, hearing loss, dizziness, tinnitus and rash around the ear.
- Facial nerve involvement causing facial paralysis.
Other rare complications include:
- scarring from bacterial infection
- post inflammatory hypopigmentation ( loss of pigmentation)
- involvement of other organs of the body such as lungs, liver, brain and spinal cord
Shingles in early pregnancy is unlikely to affect the foetus because of immunity in the past from varicella (chicken pox). You should seek prompt medical attention if shingles occurs in pregnancy.
How is shingles diagnosed?
- The clinical appearance of the rash. This may be a problem if there is no rash, the so-called “zoster sine herpete” [ZSH] or if there is an extensive rash as in immunocompromised patients.
- Viral skin swab to test for polymerase chain reaction. This test amplifies the viral DNA and can be detected by a specific probe. This test separates herpes zoster from herpes simplex.
- Blood test for the herpes zoster IgM and IgG antibodies. The interpretation of the results can be a problem at times.
How is it treated?
- For the acute phase, the usual treatment in an otherwise well adult is 800mg acyclovir five times a day for 7 to 10 days, as soon as the diagnosis is made or within 1 to 3 days if possible. The dose may be modified depending on weight, age, renal function and immune competence. Alternative medications include valaciclovir and famciclovir.
- Treatment of herpes ophthalmicus and Ramsay Hunt syndrome is usually referred to the relevant specialists for treatment.
- Bed rest, analgesia, antibiotics for secondary infection and moisturising ointment for the rash and subsequent crusting.
- Oral steroids are not recommended as treatment for the common form of shingles. There may be a role in Ramsay Hunt syndrome.
How is post herpetic neuralgia treated?
- The following treatments are available. Analgesics such as topical capsaicin cream (zostrix cream)
- Antiviral agents such as acyclovir, valaciclovir and famciclovir. The aim is to shorten the clinical course of the acute infection and post herpetic neuralgia.
- Topical anaesthetic agents such as topical lidocaine gel (5 %)
- Tricyclic antidepressants such as amitriptyline and nortriptyline
- Anticonvulsants such as gabapentin (neurontin) and pregabalin (lyrica)
- Zoster vaccine (zostavax) reduces the acute infection and the severity of post herpetic neuralgia
- Trans cutaneous nerve stimulation or acupuncture
- Botox injection to the affected area.
Prevention of shingles
A vaccination for shingles has now been introduced because of the increasing frequency and severity of shingles in older people. The vaccine, called zostavax, consists of a live attenuated strain of varicella.
The vaccine is recommended for people over the age of 60, and is free to people over the age of 70 in Australia. It consists of a single injection in the upper arm and is generally safe and well tolerated. The most common side effect is redness and swelling at the injection site.
This vaccination can reduce the severity of shingles and post herpetic neuralgia in older people.
Further information
- Medscape reference on shingles
- CDC Centers for Disease Control and Prevention information on shingles
- Mayo Clinic information on shingles
- Shingles during pregnancy
- NPS Medicinewise herpes zoster epidemiology, clinical features, treatment and prevention
This information has been written by Dr Chris J Tyson