Shingles

Introduction

Shingles is also known as herpes zoster in the medical world. It is a disease of the nerve and skin caused by the varicella zoster virus (VZV). The main risk factors are:

  1. Increasing age (more than 50 years old) due to declining immune system and
  2. 2) Suppression of the immune system due to a variety of causes e.g. human immunodeficiency virus (HIV) infection and medications (e.g. steroids).

Approximately 10% to 30% of individuals will get this condition over their lifetime.

The cause of herpes zoster is the reactivation of VZV. VZV remains dormant in the sensory nerve centre (ganglion) following primary VZV infection (chickenpox). Once the immune system is weakened, VZV is reactivated from its dormant state in the sensory ganglion causing inflammation and necrosis of the affected sensory nerve.

Signs and Symptoms

Herpes zoster usually affects one nerve distribution (dermatome) on one side of the body. The most commonly affected region is the chest (thoracic) and face (trigeminal).

The earliest manifestations of herpes zoster include pain, tingling, numbness or burning of the affected nerve distribution, headache, weakness, mild fever and malaise before appearance of skin lesions. This prodrome occurs in 80% of patients. It usually last between 3 and 5 days.

In the affected nerve region, the first sign is a few painful red spots or hives.  Within 1 or 2 days, these spots become vesicles (small blister) filled with yellowish fluid. Over the next 2 days, groups of vesicles appear along the nerve distribution. Later, the content of the vesicles become cloudy and subsequently dry out in 1 to 2 weeks. The crusts (dried out lesions) will eventually fall off in 1 to 2 weeks leaving normal skin, scar or discolored skin.

Presence of vesicles on an erythematous base over the left chest and back along the distribution of the sensory nerve

Doctors usually do not have difficulty making a diagnosis of herpes zoster if the typical skin rash with pain, burning or numbness is present along the affected nerve distribution on one side of the body. Diagnostic difficulty usually arises in the prodromal period before the appearance of skin lesions.

Complications

During the acute stage (presence of skin lesions), the skin lesions can become secondarily infected by bacteria, become hemorrhagic with presence of blood in the blisters or disseminate outside the affected nerve distribution. The last complication usually occurs in patients with suppression of the immune system. This subgroup of patients will also have the skin lesions for a prolonged period of time.

If the herpes zoster affects the face, it might cause complications to the eyes including blindness and the facial nerve (nerve innervating the facial muscle) causing facial palsy (one sided paralysis of the facial muscle). Rarely, herpes zoster might cause viral infection and inflammation of the internal organs including the brain (meningoencephalitis), heart (carditis), lung (pneumonitis) and gut (enterocolitis).

After the disappearance of the skin lesions, the affected area might have residual scar or discoloured skin. The other common chronic complication is post herpetic neuralgia (pain in the nerve distribution after having shingles for a prolonged period of time). This complication is most commonly seen in the elderly (over 65 years old). The persistent pain can cause severe impairment in the quality of life. Other less common chronic complications include eye complications (inflammation and blindness) and nerve complications (nerve and spinal cord inflammation and physical disability).

Treatment

The aim of therapy is to:

  1. Relieve pain.
  2. Limit the spread and duration of skin lesions.
  3. Prevent complications especially post herpeic neuralgia.

Relieve of pain can be achieved through:

  1. Local measures like application of drying agents e.g. potassium permanganate for vesicles and fluid discharge.
  2. Administration of painkillers like non steroidal anti-inflammatory drugs (NSAIDs) e.g. diclofenac and
  3. Administration of neuroactive agents e.g. amitryptiline.

Administration of effective antivitral agents within hours of onset of skin lesions can help prevent complications and limit the spread and duration of the disease. The antiviral agents include oral acyclovir, valacyclovir and famciclovir. These antiviral agents are usually given for 1 week. Rarely, patients with severe disseminated disease and patients with immune suppression will need admission to the hospital and be administered with intravenous antiviral agents.

Patients with facial involvement near the eyes will need to be urgently seen by the ophthalmologist (eye specialist). The ophthalmologist will look for eye involvement of the disease to prevent complications especially blindness. Appropriate treatment will be administered if there is eye involvement.

Zoster vaccine can be given to prevent shingles in those aged 60 and above with no contraindication to the vaccine.

Last Reviewed : 20 June 2014
Writer : Dr. Felix Yap Boon Bin
Accreditor/Reviewer : Datin Dr. Asmah bt. Johar