Postherpetic Neuralgia

Symptoms

Postherpetic neuralgia manifests as localizable and unilateral pain in the area that was affected by shingles, increased tenderness (allodynia¹) and pruritus. The pain character is described as itchy, burning, sharp, stabbing, and throbbing, among others. The discomfort occurs even though the shingles has healed and can sometimes last for months and even years. The pain affects the mind, can severely disrupt normal daily activities and sleep, and can reduce the quality of life. Elderly and immunosuppressed individuals are particularly affected. ¹ Allodynia: Pain is triggered by even mild mechanical stimuli such as clothing or a light touch.

Causes

Postherpetic neuralgia is a nerve pain that is caused by a disease of the peripheral nerve fibers. It is caused by shingles, which is the endogenous reactivation of the varicella-zoster virus, a DNA virus in the herpes family that causes chickenpox in childhood and remains dormant in the body for decades. Important risk factors include age, immunosuppression, disease, and stress.

Diagnosis

Diagnosis is made in medical treatment based on patient history (previous shingles) and physical examination. A pain questionnaire, pain diary, and visual analog scale may be used as aids and to monitor progress.

Prevention

• The vaccine Zostavax is approved for the prevention of shingles and postherpetic neuralgia.
• Early treatment of shingles with nucleoside analogues (eg, aciclovir, famciclovir, valaciclovir) may reduce the risk.

Drug treatment

For drug treatment, primarily the so-called co-analgesics are used, which affect the conduction and perception of pain:

• Antiepileptic drugs, e.g., gabapentin (Neurontin, generics), pregabalin (Lyrica).
• Antidepressants, such as tricyclic antidepressants, have analgesic, mood elevating, and sleep inducing properties
• Other co-analgesics, such as NMDA antagonists.

Systemic analgesics are centrally or peripherally analgesic:

• Opioids, e.g., morphine, oxycodone, tramadol.
• Paracetamol and NSAIDs are considered insufficiently effective, a therapy attempt is possible.

Local preparations:

• Capsaicin in the form of a capsaicin cream or as a capsaicin patch (Qutenza).
• Lidocaine patches (Neurodol).

Non-drug treatment

Non-drug treatment measures include:

• Cold, such as cold pads (generally better than heat).
• Physical therapy, e.g., TENS (Transcutaneous Electrical Nerve Stimulation).
• Acupuncture, acupressure
• Wraps, poultices
• Distraction, relaxation techniques