Dr. Hanna Saadah

Shingles represents an episode of self-reinfection with the chicken pox virus, Varicella Zoster.  As children, we usually acquire chicken pox naturally through inhalation.  It presents with fever and a generalized rash characterized by blisters that are central (more on the trunk than the extremities) and in different stages of development (some are old and scabbed over, some are new, and some are in between).  The disease was first described by the Persian physician Muhammad ibn Zakariya ar-Razi (865–925) who distinguished it from the more deadly small pox.

The Varicella Zoster virus, which is extremely contagious, is usually acquired by inhaling contaminated air particles coughed by children with active chicken pox.  When the infection subsides, the virus goes to sleep inside the sensory nerve cells of the spinal cord and brain where it remains dormant for the rest of the individual’s life.  However, as individuals age and their immunity wanes, the virus tends to make occasional sorties from its hiding places, each time attacking one circumscribed skin zone innervated by one sensory nerve root.  This limited form of adult chicken pox is commonly known as Shingles.

            Shingles increases with age—the annual incidence of Shingles is about 1.2—3.4 cases per 1000 healthy younger adults and 3.9—11.8 cases per 1000 adults older than 65.  The consequences of Shingles are both acute and chronic.  Acutely, the eruption causes a painful misery to a large zone of skin on one side of the body and the blisters take about three weeks to dry up.  However, after the blisters dry up and heal, a residual, regional pain may continue on for weeks, months, or even years.  This lingering, electric, regional pain that follows a Shingles attack is called Post Zoster Neuralgia.

            Post Zoster Neuralgia is caused by damage to the sensory nerves that collectively form the sensory nerve roots, which emerge out of the spinal cord or brain.  Apparently, as the virus multiplies in the cell bodies of these sensory nerves and then travels along the nerve highways to the skin, it inflicts damage along the way.  Some unfortunate victims may have to live with these ‘electric nerve pains’ for the rest of their lives.  Luckily, however, the lingering pains of Post Zoster Neuralgia are rare in individuals under 50 and tend to wear off quickly.  In older individuals, although the pains tend to wear off more slowly, up to 85% will usually become pain free one year after their Shingles.

            Treatment is of two types.  Preventive treatment is far superior and involves vaccination of older adults.  Abortive treatment involves giving antiviral medications that arrest the progression of the eruption and shorten the duration of the blistering and pain.

            The adult vaccine, Zostavax, was officially endorsed in 2007 for individuals 60 years or older.  It prevents about half the cases of expected Shingles and reduces the Post Zoster Neuralgia incidence by about two-thirds.  The vaccine contains a living virus that has been attenuated (rendered unaggressive and undamaging) by laboratory methods.  Nevertheless, it can attack individuals who have reduced immunity due to cancer, chemotherapy, cortisone, etc. or individuals with damaged skins due to trauma, burns, rashes, etc.

            Vaccination of children against chicken pox began in 1995 and has greatly reduced the incidence of natural infection.  As a consequence, when those vaccinated children become adults, they are expected to a) have less Shingles than those who had acquired the infection naturally and b) develop less Post Zoster Neuralgia as older adults.

            Abortive treatment of Shingles involves giving antiviral medications but the window of opportunity is narrow.  Medications such as Acyclovir inhibit viral replication inside the nerves, shorten the duration of the blistering, but may not reduce the incidence or duration of the Post Zoster Neuralgia.  Treatment is most effective when begun early and tends to lose its effects if given more than three days after the rash.

            Early Shingles symptoms may begin few hours to few days before the rash appears.  Unexplainable shooting, electric pains that affect one sensory nerve zone on one side of the body—such as face, trunk, or extremities— and do not cross over to the opposite side, should be clinically diagnosed as Shingles and treated before the typical rash appears.  Delaying treatment until the rash appears may result in poorer outcomes.

            Confusion between Shingles and Herpes is common because the viruses have similarities such as one-sided pains before the rashes appear and blisters in circumscribed skin areas.  However, the blisters of Herpes tend to be recurrent to the same spots, are of shorter durations (few days), develop in smaller areas (few blisters in an area as big as a coin), and seldom result in post herpetic neuralgias.  Shingles, on the other hand, affects larger skin areas and is not recurrent to the same spots.  While over a lifetime an individual may develop a maximum of three Shingles episodes, most herpes sufferers will experience numerous, recurring episodes of blistering to the very same locations.