Postherpetic Neuralgia - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Postherpetic neuralgia is a condition caused by a complication of herpes zoster or shingles infection. The condition occurs due to the reactivation of herpes zoster, which also causes chicken pox. The symptoms produced by shingles are very itchy and painful rashes or blisters occurring on one side of the body, especially in the center of the body, in a band pattern. The symptoms, such as rash or blisters, may get resolved in some people, but the pain can still be present on the clear skin of a person. This pain is referred to as postherpetic neuralgia, caused as a complication of shingles. The article discusses the causes, symptoms, treatment, and preventive measures for postherpetic neuralgia.

What Are the Causes of Postherpetic Neuralgia?

Postherpetic neuralgia pain mainly occurs due to shingles caused by Herpes Varicella Zoster Virus that cause chickenpox. The virus remains inactive in the person’s body after they recover from chicken pox. However, the inactivated virus can become activated in the future and cause skin and nerve infections called shingles. It affects the nerves of the abdomen and chest on one side of the body and, thus, affects the functioning of the nerves. The damaged nerves send random, confused, and chaotic pain messages to the brain. This leads to burning and throbbing painful conditions along the nerves.

Shingles are believed to create pressure next to the nerves by forming scar tissue, thus giving pain signals to the brain.

What Are the Symptoms of Postherpetic Neuralgia?

The symptoms of postherpetic neuralgia are as follows:

• Aching, burning, jagging, and sharp pain occur when rashes or shingles appear in the affected area.

• Numbness and itching around the area where the rash has appeared.

• The affected area is sensitive to touch, and the pain can get triggered with a slight touch. In addition, a burning sensation can be felt on the affected skin area.

• The pain of postherpetic neuralgia usually lasts for at least three months, and the pain keeps coming and going or remains constant throughout.

• Postherpetic neuralgia pain aggravates in cold or hot temperatures and also at night.

• In some cases, postherpetic neuralgia can cause paralysis or muscle weakness.

• It may also cause sleeping difficulty and fatigue in a person.

What Are the Risk Factors for Developing Postherpetic Neuralgia?

The risk factors are as follows:

• Weakened Immune System: With growing age, a person's immune system gets compromised, which leads to the reactivation of the Varicella-Zoster virus, and Shingles occur in people due to this. The medical conditions affecting the person’s immunity include HIV (human immunodeficiency virus)/ AIDS (acquired immunodeficiency syndrome), cancer, etc. It can also occur due to certain medications, such as steroids, chemotherapy, anti-organ rejection medicine, and chemotherapy.

• Old Age: A person's growing age makes them more susceptible to developing postherpetic neuralgia than younger people. If a person gets affected with shingles, they are more likely to develop post-herpetic neuralgia. Shingles usually occur in almost 10 to 13 percent of people above 50 years of age, with severe pain and long-lasting effects, and further develop postherpetic neuralgia.

• The Severity of Shingles: More severe the shingles rash develops, the more the chances of developing postherpetic neuralgia.

• Itchy or Painful Feeling Before Shingles Rash Appear: If a person experiences these symptoms before the shingles appear, they are at greater risk of developing postherpetic neuralgia.

• Delayed Treatment: If a person does not consult the doctor within three days after the rash appears on the body, they often miss the opportunity to receive the antiviral drugs on time and, therefore, develop postherpetic neuralgia.

How Is Postherpetic Neuralgia Treated?

The doctor can treat postherpetic neuralgia with a variety of medications. Over-the-counter painkillers are given to a person with mild symptoms. However, the more severe condition is treated with narcotic or opioid painkillers, which include Methadone, Meperidine, Morphine, long-lasting Hydrocodone, Hydrocodone with Acetaminophen, Oxycodone, Naloxone, etc. In addition, anticonvulsant medications used to treat seizures are also prescribed for postherpetic neuralgia pain. These medications include Pregabalin, Carbamazepine, and Gabapentin. Also, tricyclic antidepressants, such as Desipramine, Amitriptyline, and Nortriptyline, are prescribed to treat pain caused by postherpetic neuralgia. Sometimes, a topical treatment for pain relief is also given to the patient, which includes Lidocaine patches, Capsaicin cream, Ibuprofen, or Acetaminophen.

How to Ease the Pain Caused by Postherpetic Neuralgia?

Pain caused by postherpetic neuralgia can be eased in the following ways:

• Gel-filled cold packs can numb the painful area. However, the method can be used only if the cold does not exaggerate the pain in a person.

• Transcutaneous electric nerve stimulation (TENS) device is used in the pain area to shoot tiny electric currents to numb or block the pain.

• In addition, wearing loose-fitted and comfortable clothes made of cotton can ease the pain.

How Is Postherpetic Neuralgia Prevented?

Two shingles vaccines such as Shingrix and Zostavax, have been approved by the Food and Drug Administration (FDA) to prevent the condition. The vaccine can reduce the risk of shingles by up to 50 %. Those who develop shingles after vaccination have less severe pain symptoms and have fewer chances of developing postherpetic neuralgia. Also, proper treatment of singles in its early phase can reduce the risk of postherpetic neuralgia. Therefore, a person experiencing the symptoms of rash, pain, or itching should consult the doctor within three days to minimize the fatal consequences and get timely treatment.

What Are the Complications Related to Postherpetic Neuralgia?

The complications of postherpetic neuralgia include

• Decreased appetite.

• Tiredness.

• Insomnia or sleeping difficulties.

• Poor or lack of concentration.

• Depression due to severe pain.

Conclusion

The risk of developing postherpetic neuralgia increases with age, and the condition is challenging to treat. Therefore, the initial diagnosis of postherpetic neuralgia plays a crucial role in treating the condition with antiviral drug therapy. These medications can reduce the risk of postherpetic neuralgia if herpes zoster infections are treated timely. Therefore, a person should immediately contact the doctor if they experience postherpetic neuralgia symptoms and take preventive measures for herpes zoster infections.