Shingles: Diagnosis, Treatment and Prevention

Shingles is a skin disease caused by a viral infection. This is also known as herpes zoster. Shingles can occur in anyone but is seen more commonly in individuals over the age of 60. According to the CDC, approximately 30% of individuals in the United States of America will manifest the infection at some point during their lifetime.

Causative Virus

The virus causing shingles is the Varicella zoster. This is the same virus causing chicken-pox. The virus is released through the skin rash blister and enters the body by direct contact and inhalation. This virus upon entering the body has an affinity for the nerves and resides in a place called the ‘dorsal nerve root ganglion’. While resting here, the person does not experience any symptoms. The virus can stay dormant here for several years. In the presence of risk factors, the virus gets reactivated to cause symptoms of shingles.

Risk factors for Shingles

Prior infection with chickenpox: After a chickenpox infection, the virus stays in the body in the nerve roots until reactivated.
Old age: the incidence increases with increasing age.
Decrease in immunity: with a reduction in immunity, the virus actively causes disease without any resistance. This can occur in various situations
Inherited immune deficiency disease
HIV and AIDS
Immunity suppressing drugs: steroids and immunomodulators
Transplant recipients who are on immunosuppressive drugs
Transient infections or other diseases such as cancer

Symptoms of Shingles

Shingles present as a skin rash with the following features

Skin rash with multiple clusters of vesicles or fluid-filled blisters. These appear on only a limited area of the body on only one side. The rash may appear on the face as well.
Burning pain in the area of the rash. This may precede the rash and often persists after the rash resolves

Diagnosis of Shingles

The diagnosis is apparent in the clinical examination of the rash with its characteristic distribution. Additional tests are not necessary for confirming the diagnosis.

If deemed necessary in unclear cases, the viral DNA can be detected from scrapings of the blisters.

Treatment of Shingles

Early treatment of shingles is necessary for maximum benefit. The following are general recommendations for treatment.

Antiviral therapy: Oral antiviral medicines (acyclovir, valacyclovir, or famciclovir) to target the virus are administered in adequate dosage. The benefit is noted only when initiated within 72 hours from the appearance of a rash.
Pain management: Non-steroidal anti-inflammatory drugs (NSAIDs) can be helpful for pain relief, either alone or along with a weak opioid like oxycodone. These should be taken only after a recommendation from a physician.
Improvement in immunity: If the underlying cause is poor immunity, modification of immunosuppressive drugs or treatment of the underlying disease ought to be considered.

Complications of Shingles

Postherpetic neuralgia: This is a condition where severe burning pain persists even after resolution of the rash. This occurs in 10 – 15% of patients experiencing shingles. Early antiviral therapy has an unclear benefit. This is usually managed with medicines such as tricyclic antidepressants, gabapentin, or pregabalin.
Vision disturbance: When the virus affects the face around the region of the eye, it can damage the cornea and the retina, with a high risk of blindness. Early antiviral therapy can prevent this.
Secondary bacterial infection: The rash may develop a superadded bacterial infection. This would be suspected from redness, warmth, and pus around the blisters. Antibiotics are needed for treatment.
Ramsay Hunt Syndrome: This occurs when the nerve supplying the facial muscles and skin over the ear canal gets affected, leading to one sided facial paralysis, ear pain, and blisters in the ear canal. It is treated with antivirals and steroids.

Prognosis of Shingles

The shingles rash resolves completely with appropriate antiviral therapy. The pain is harder to manage and persist as postherpetic neuralgia.

1 in 4 individuals developing shingles has a risk of a second attack.

Prevention of Shingles

Vaccination is successful in decreasing the incidence of shingles and is recommended in all individuals over the age of 50 years irrespective of prior infection with chickenpox or shingles.

There are presently 2 types of vaccines available:

Live attenuated vaccine: This is the traditional vaccine that is the available world over to prevent shingles. It requires only one dose.
Non-live Recombinant vaccine: This is a new vaccine approved from October 2017 for use in the US. It is currently the preferred vaccine in individuals with intact immunity. It requires 2 doses.

References:

Stankus SJ, Dlugopolski M, Packer D. Management of Herpes Zoster (Shingles) and Postherpetic Neuralgia. AFP. 2000 Apr 15;61(8):2437.
Shingles | Overview | Herpes Zoster | CDC [Internet]. 2018 [cited 2018 May 24]. Available from: https://www.cdc.gov/shingles/about/overview.html