Herpes zoster

Herpes zoster or shingles affects 20% of the adult population and occurs most commonly in individuals over the age of 50 years. The terms herpes zoster are of Greek origin, herpes meaning "to creep" and zoster meaning "girdle" or "belt".

Cause
Herpes zoster is caused by the reactivation of the varicella-zoster virus (VZV) that has taken up residence in a nerve cell following chickenpox (varicella). Reactivation is believed to be caused by lowered body immunity (resistance) due to:



• Old age.
• Underlying cancer.
• Drugs which may suppress immunity, for example anti-cancer drugs and systemic steroids (i.e., steroids taken by mouth or injected).
• X-ray therapy.
• AIDS (acquired immune deficiency syndrome)

   

  Symptoms

• The earliest symptom is burning, itching, tingling or pain which may precede the rash by 4 - 5 days.
• A line or cluster of blisters develop on one side of the body corresponding to the distribution of the nerve in which the old varicella-zoster virus has taken up residence.
• Blisters ulcerate, crust over and form dry scabs. These heal after 2 - 3 weeks, leaving scars.
• Pain, which may be severe and prolonged, lasting for several months.
• Fever, malaise (feeling of illness) and headache.

  Herpes zoster. Click on image for larger view

  Complications

• Herpes zoster affecting the 5th cranial nerve may involve the cornea (transparent covering of the eye), causing scarring and visual impairment. The risk of this occurring is increased when blisters appear on the sides or tip of the nose.
• Dissemination - herpes zoster may spread ouside the distribution of the nerve and cause disseminated herpes zoster in individuals with underlying cancers (such as leukaemia and lymphoma) and those on immunosuppressive drugs.
• Ramsay Hunt syndrome due to involvement of the 7th and 8th facial nerve causing facial paralysis, tinitus (ringing in the ear), vertigo (giddiness with the room spinning around) and blisters on the tongue, the ear and its canal.
• Postherpetic neuralgia - This is defined as pain that has persisted at least 4 weeks after the appearance of the rash. Twenty per cent of those over 60 years of age may be affected. Postherpetic neuralgia causes itching, tingling, burning and sharp shooting pains. The pain may precipitated by light touch over the affected area and can be extremely debilitating. It is difficult to treat.

  What you can do

• You should consult a doctor early as treatment is most effective when treatment is started within 72 hours of the appearance of the rash.
• Take painkillers.
• Take antihistamines if there is itching.
• Apply saline compresses to dry up the blisters and keep the area clean.
• Avoid contact with children who have not had chickenpox before because there is a small risk of transmitting the virus to children, causing chicken pox. Adults usually are not at risk since most of them had already had chickenpox and herpes zoster would be a reactivation of this old virus within themselves rather than from another person.

  What the doctor may do

• Confirm the diagnosis.
• Refer to an ophthalmologist if there is eye involvement.
• Prescribe strong painkillers and antihistamines.
• Prescribe acyclovir, valcyclovir or famcyclovir to reduce symptoms and hasten recovery. Treatment also reduces the risk of postherpetic neuralgia.
• Treat postherpetic neuralgia - antidepressants, tranquillisers, intralesional steroid injections into the painful areas, strong painkillers, carbamezapine, pimozide, capsaicin cream, TENS (transcutaneous electrical nerve stimulation) and sympathetic nerve block may be tried in this very difficult problem.

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