What is Shingles?
Shingles is a painful, viral skin disease due to the reactivation of the varicella-zoster virus (VZV). The initial infection of VZV is chickenpox, and once that resolves, VZV stays dormant in the nerve cells of the body. It is characterized by blisters and a skin rash localized to specific areas of the body.
Shingles is a common viral disease, affecting 1 in 3 Americans at some point in their life. It is more common in adults, however, children may also contract this disease.
What causes Shingles?
Shingles, also known as Herpes zoster or just zoster, is caused by the varicella-zoster virus, a double-stranded virus. This virus is related to the herpes simplex virus and causes chickenpox in children. After the initial attack, VZV is cleared out by the immune system. But it may remain latent in the dorsal root ganglion in the spine or trigeminal ganglion at the base of the skull.
Normally, the immune system will suppress the reactivation of VZV but sometimes attacks may evade the immune system. The exact mechanism of this is not known but attacks of shingles are associated with aging, stress, and immunosuppressive therapy.
VZV results in chickenpox and then, shingles. It is not possible for an individual to be affected by SHingles and not have contracted chickenpox. Also, the recurrence rate of shingles is very low. Most affected patients only get Shingles once in their lifetime.
After the initial infection, the virus may become dormant but it keeps on producing virus-specific proteins. Upon reactivation, the virus transforms from its latent lysogenic cycle to the lytic cycle. It starts producing virions and releasing them to be carried down the axons to skin innervated by the ganglion in which the virus resides. The virus, upon reaching the skin, causes painful blisters, inflammation, and rash.
Touching of rashes can help transmit VZV, although the healthy individual, if not vaccinated, will get infected and contract chickenpox first.
What are the signs & symptoms of Shingles?
Shingles, in their early stages, presents with non-specific, constitutional symptoms like fever, malaise, and headache. But as the disease develops, more specific symptoms like burning pain, paresthesias, oversensitivity, and pruritus appear.
2 days to 3 weeks later, characteristic symptoms of Shingles begin; painful skin rash that affects a dermatome. This rash may start off as hives and results in a belt-like rash. If this rash doesn’t develop, but all the other symptoms do, the patient is said to be Zoster sine herpete (zoster without herpes).
The rash then turns into vesicular blisters with serous exudate. These vesicles may become darkened as the exudate gets filled with blood, and within 7 to 10 days, a crust might develop around these vesicles. This crush eventually falls off, leaving behind healed skin but in some cases, it may cause discoloration or scarring of the skin.
The pain associated with Shingles can vary from mild to extreme and can present in various patterns such as throbbing, numbing, tingling, aching. The typical presentation of pain is throbbing, numbing, aching pain with stabs of agonizing pain in between.
Shingles, especially if VZV was latent in the trigeminal ganglion, can affect the face with a range of symptoms. The most common nerve involved is the ophthalmic division of the trigeminal nerve. It’s referred to as zoster ophthalmicus. It affects the upper eyelid, eye orbit, and skin of the forehead, presenting with conjunctivitis, uveitis, keratitis, debilitating pain, and optic nerve palsies.
If it involves the ear, it is known as Shingles oticus or Ramsay Hunt Syndrome Type II. VZV passes through the facial nerve to reach the vestibulocochlear near to cause shingles oticus and can cause hearing loss and vertigo.
If the virions reach the mandibular or maxillary divisions of the trigeminal nerve, they can cause oral shingles which are commonly misdiagnosed as tooth pain. Oral shingles, depending on which division is affected, cause a rash on mucous membranes of the upper or lower jaw.
If Shingles affects immunocompromised individuals, it can result in a widespread rash and involve organs other than skin. This is known as disseminated shingles and commonly involves the brain and liver. If not treated, it has the potential to be lethal as it can cause hepatitis and encephalitis.
How do you diagnose Shingles?
The diagnosis of shingles is clinical if the rash has developed. Shingles rash follows a dermatome map and is very distinct, hence an easy diagnosis based on visual examination. However, if the rash has yet not developed, diagnosis is difficult.
Checking for VZV Immunoglobulin M in the blood may show if there is an active infection present at the time of the test. Along with that, exudate/lymph from the blisters may be studied either under an electron microscope or using PCR. Electron microscopy may show virion particles and PCR is done on VZV DNA.
The most reliable method of diagnosis right now is PCR, due to its higher sensitivity, low risk of contamination, and overall rapid results.
What is the differential diagnosis of shingles?
Shingles may be misdiagnosed as many other skin conditions like:
● Herpes Simplex
● Herpetiformis dermatitis
● Contact dermatitis
How do you treat shingles?
The aim of treatment is to manage pain, shorten the duration of the episode, and overall reduce the risk of complications. For this purpose, the following medications may be taken;
- Painkillers (Analgesics): OTC painkillers may relieve the pain associated with shingles. Calamine may provide a soothing effect. FDA recently approved the use of capsaicin (Zostrix) ointment on crusted lesions.
- Antivirals: These drugs can help decrease the severity and shorten the duration but do not reduce the risk of complications. The most commonly used antiviral is Acyclovir. If given intravenously, it may prevent complications in immunocompromised individuals
Can shingles be prevented?
Shingles can be prevented with VZV vaccination before an individual gets chickenpox. If chickenpox has already been presented, there are specific shingles vaccines. FDA has approved the live attenuated virus vaccine, Zostavax and it has been proven to protect from a shingles attack for three years. There is also an adjuvant subunit vaccine, Shingrix that is used.
What are the complications of shingles?
The most common and severe complication of shingles is postherpetic neuralgia. This develops in the same area as the shingles rash and is extremely painful. So much so that it can negatively impact the daily life of affected individuals.
Other complications include:
- Motor weakness
- Pneumonia or secondary bacterial infections
- The blindness of trigeminal shingles
- Ear damage
Shingles are the reactivation of a viral infection caused by VZV. It usually causes a rash that can be misdiagnosed as other dermatological or infectious etiology. The use of shingles vaccines and boosters can prevent a shingles attack. The vaccine is FDA approved and recommended for use. Also, while treating shingles, it is important to do follow-ups to make sure that it hasn’t caused any complications in affected individuals. Proper diagnosis and follow-up are crucial for a good prognosis.