What is postherpetic neuralgia (PHN)?

Postherpetic neuralgia is a chronic pain condition that affects your nerves and skin. It results from nerve damage caused by shingles, which is a product of the varicella-zoster virus (this is the same virus that causes chickenpox). When the virus causes a shingles outbreak, it manifests itself as a rash on your skin, which may blister and cause pain for up to a month. If after that time, the rash is gone but there is still pain, it is usually postherpetic neuralgia. Only a minority of shingles outbreaks result in this condition.

Postherpetic neuralgia is pain from shingles that persists after the rash has healed. It is most common in older people. The pain can be mild or severe -- the most severe cases can lead to insomnia, weight loss, depression, and disability. Postherpetic neuralgia is not directly life-threatening. About a dozen medications in four categories have been shown in clinical trials to provide some pain relief. These categories are:

Tricyclic antidepressants (TCAs): TCAs are often the first type of drug given to patients suffering from postherpetic neuralgia. TCA amitryptiline was commonly prescribed in the past. Although it is effective, it has a high rate of side effects. Desipramine and nortriptyline have fewer side effects and are therefore better choices for older adults, the most likely group to have postherpetic neuralgia.

Anticonvulsants: Some drugs that reduce seizures can also treat postherpetic neuralgia because seizures and pain both involve abnormally increased firing of nerve cells. An antiseizure medication, carbamazepine, is effective for postherpetic neuralgia but has rare, potentially dangerous side effects. So, a newer anticonvulsant, gabapentin, is far more often prescribed. The side effects of this drug include drowsiness or confusion, dizziness, and sometimes ankle swelling.

Opioids: Opioids are strong pain medications used for all types of pain. They include oxycodone, morphine, tramadol, and methadone. Opioids can have side effects including drowsiness, mental dulling, and constipation. Further, opioids can be addictive, so their use must be monitored carefully in those with a history of addiction.

Topical local anesthetics: Local anesthetics applied directly to the skin of the painful area affected by postherpetic neuralgia are also effective. Lidocaine, the most commonly prescribed, is available in cream, gel, or spray form.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke.
Ryan Church, DNP
Postherpetic neuralgia (PHN) is a condition that is very painful and can be devastating to people who have it. It's the chronic pain that happens after the shingles virus or herpes zoster virus has run its course. It is a condition where a person has permanent nerve damage and can feel a wide range of severely painful sensations in the area where they had shingles.

It never really goes away because it's nerve damage and the nerves in the area are sending aberrant pain signals to the brain.

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