Shingle Pain and Post-herpetic Neuralgia

Many believe that chickenpox can only be contracted once in a lifetime. Most adults even recall chickenpox as a “rite of passage”, and dote on childhood memories of connecting the red bumps on their bodies with marker. Most people even think that contracting chickenpox would result in immunity to the virus later in life. However, this isn’t the case–the varicella zoster present in chickenpox, has viral latency, which means it can lie dormant until the environment is favorable, such as when the host in undergoing immunosuppression. So even if you’ve had chickenpox as a child, it is possible to contract the virus again.

Shingles, also known as herpes zoster, is a viral infection and a result of “reanimated” varicella zoster virus. Upon initial infection of the varicella zoster virus (chickenpox), the virus invades the sensory nervous system, traveling up the skin to the trigeminal or dorsal root ganglia, where it can remains dormant for years. Should the varicella zoster virus become reactivated, through age or through compromised immune health, it travels back along the nerves to the skin. The result is of this reactivation is what we know as shingles.

Herpes zoster is characterized by the development of vesicular pain that follows the route of cranial or spinal nerves inflamed by the virus. The first symptoms include unilaterally distributed pain and vesicular eruptions. Soon afterwards is the appearance of red patches and blisters that crust over. During the first few days, the clinical presentation is a burning or itching sensation along the face or abdomen. Four to six days consequently, the skin inflames and becomes a shade of red, followed by a cloudy fluid of vesicles. Once these vesicles rupture, it develops a crust and flakes off in 2-3 weeks.  Treatments for shingle pain include administration of antiviral agents such as acyclovir, valacyclovir, famiciclovir, are prescribed to reduce the severity of Herpes Zoster. Analegesics, antihistamines, Opiates, antidepressants, corticosteroids, and anticonvulsants are also prescribed as pharmacologic agents to alleviate pain. Every case is different, however, and only a medical professional will know what is right for you.

For most patients with shingles, the rash goes away with the pain. But 15% of all patients have long-lasting shingles pain, otherwise known as postherpetic neuralgia, left by nerve damage. The viral reactivation affects nerve fibers, causing burning pain that persists for more than 90 days after the blisters and skin eruptions cease to exist. Symptoms include the sensation of burning, jabbing, and aching for pain that persists for three months or longer. Patients also experience allodynia, hypersensitivity to touch, and numbness. Postherpetic neuralgia can adversely affect daily activity. For example, patients have described lack of sleep because even bed sheets can induce unbearable pain when sheets come in contact with lesions in the skin. Even when there is no stimulus, patients have reported to perceive excruciating pain.

Unfortunately, there is no cure for postherpetic neuralgia, and is often difficult to treat. No single treatment minimizes symptoms, which means trial and error is needed in finding the right medication. The first line of treatments is topical agents, such as lidocain, and capsaicin transdermal patches. These patches, available by prescription, can directly deliver temporary relief. Initially, capsaicin causes a burning sensation, because it is a high extraction of chili peppers. But with repeated use, pain is alleviated. Certain anticonvulsants, which treat seizures, can lessen the pain. Medication including gabapentin and pregabalin can stabilize abnormal neuron signaling caused by destroyed nerves. Antidepressants may also affect how brain chemicals play in how your body interprets pain. Nortriptyline, Duloxetine, and venlafaxine are often prescribed for their analgesic properties. In final measures, some may need prescription Opioid painkillers such as tramadol, oxycodone, or morphine. Opioid use is controversial because they may lead to addiction, emotional disturbances, and sedation. For preventative measures, the herpes zoster vaccine, Zostavax, have shown to greatly decrease the severity and incidence of shingles and postherpetic neuralgia. It is approved by the FDA for is recommended for all adults 60 and older.

Unfortunately, if you are dealing with postherpetic neuralgia, your pain is the aftermath of a viral infection. It is imperative that you and your doctor develop a pain management plan to address your condition.

Joyce Woo