Shingles is a painful skin condition that people associate in their minds with chickenpox. It is, in fact, caused by a re-emergence of the virus that causes chickenpox (varicella), many years after the original childhood illness. Shingles (also known as herpes zoster) is becoming increasingly common in elderly people, largely because people are living longer, and more of them have a reduced function of their immune systems. It is said that of those over 60 who have had chickenpox as a child, half are likely to develop shingles by the time they reach 85. A recent review has been published that covers the main features of this quite distressing condition.
Who gets shingles?
Reactivation of the varicella virus that is lurking in the nerve roots near the spinal cord and the brain occurs because the immune system that normally keeps it under control is defective. This can be due to age, or because of a condition that interferes with the immune cells e.g. cancer, or the need to take an immunosuppressant drug. Although blood and lymph cancers are associated with a high risk of shingles, solid tumors are not. The effect of age is demonstrated by one study, which showed that one third of all healthy elderly people tested had a low or an absent cell response to the herpes virus, compared with none of those in a 20-40 age group who were also tested.
An interesting fact is that African Americans in the USA are four times less likely to suffer from shingles than white people living in the same area. This may be due to differences in their exposure to chickenpox, or re-exposure during their lives.
The most important clinical feature of shingles is pain. It’s usually the first symptom – either intense or variable in nature, sometimes accompanied by flu-like symptoms (fever, muscle aches, etc.). The pain occurs only on one side, and, until the rash appears some days or even weeks later, the diagnosis can be quite difficult. Sometimes conditions such as acute cholecystitis (inflammation of the gallbladder) are suspected.
The diagnosis becomes obvious when the rash appears; this starts off as a reddening of the skin, which then develops small bumps that rapidly become small blisters. The distribution follows the affected nerve supply, usually starting at the back and extending round towards the front of the body; it’s always just on one side.
Antiviral treatment must be started within 72 hours of the appearance of the rash, if one wants to get a rapid cure without complications. Unfortunately, there is often a delay before treatment is begun; elderly people often don’t want to bother their physicians, for a variety of reasons.
The little blisters contain fluid that carries the virus, and is infectious to other people. People who haven’t had chickenpox, especially women of childbearing age, should avoid contact with the patient until the blisters have crusted over. There is no serious risk for older contacts – over 95 percent of the adult population have got cells that can respond to the virus in their blood.
The most common complication of shingles is a distressing complaint called post-herpetic neuralgia, or PHN. One to three months after the rash has appeared pain occurs in the same area. The pain can be severe, long lasting and is also variable; It may be a deep ache, punctuated by sharp stabbing pains, and associated with muscle contractions.
Older people are far more likely to have PHN. Over 65% of untreated shingles patients over 60 had PHN in one study, compared with only 10% of those under 40. Moreover, a duration of PHN for over one year occurred in almost half the affected cases in people over 70, compared with less than 5% in younger persons. This shows that elderly people are extremely susceptible to PHN, although there is no good explanation for this.
There are other, even more serious complications of shingles in the elderly, but they are fortunately quite rare. They include loss of vision (due to shingles of the ophthalmic nerve), paralysis of the face or limb muscles, and inflammation of the brain, liver or lungs.
As we have noted, the consequences of shingles are sufficiently serious that it’s important to see your physician early on – certainly as soon as you see the rash. Antiviral drugs (acyclovir, famciclovir and valocyclovir) are the mainstays of treatment. They have relatively few side effects (nausea, diarrhea, headache).
Corticosteroid drugs (e.g. prednisone) have been used in the past to help with the pain of acute shingles. However, they are not helpful in reducing the risk of PHN, even if acyclovir is given as well.
The risk of infection must be born in mind. Firstly, one must take precautions to prevent staff members and friends who are at risk from getting infected (i.e. those who have not had chickenpox). However, most adults are not in this class. From the patient’s point of view, it may be necessary to institute very strict precautions if they have immune-suppression, so that other organisms do not infect the shingles lesions.
Vaccination against the virus (varicella) is available for children, and now large-scale clinical trials are being done in elderly patients in the USA. It has been shown that the vaccines can increase responses to the virus by the vaccinated person’s blood, but we don’t know yet whether they can prevent the occurrence of shingles or the frequency of PHN in older people. However, if a vaccine can be found that will prove effective in these respects, it will help render this distressing disease a thing of the past for elderly people.