Post infection (postherpetic) neuralgia

What is postherpetic neuralgia?

Postherpetic neuralgia (PHN) is a condition which affects your nerves and skin. It is the most common complication of shingles (also known as herpes zoster), a viral infection that affects your nerves and the skin surrounding it, resulting in a painful rash. When pain from shingles continues even after the rash subsides, it is known as postherpetic neuralgia. Pain from PHN is often described as an “intense burning sensation”, and may last for anywhere between a few months to more than a year. 

Research has shown that PHN occurs in 1 in 5 patients with shingles [1], and is more common in those aged 55 and above [2]. 

the-neurology-practice-postherpetic

Image depicting postherpetic neuralgia.

Taken from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3693437/

How will having PHN affect me?

For many, the most difficult part about having PHN is the pain that comes with it. In some cases, you may experience pain that is so severe that it affects your day-to-day life. Even activities such as putting on and wearing clothing may become extremely painful. You may also experience difficulties sleeping due to the pain. 

In addition, having to endure this physical pain may in turn negatively affect your mental health and render you fatigued and exhausted as well. 

What does having PHN feel like?

In general, the symptoms of PHN are restricted only to the areas previously affected by the shingles infection. 

Pain. The main tell-tale sign of PHN is the intense, unsubsiding pain that lasts for more than 3 to 4 months even after your shingles rashes have healed. Majority of people experience pain that can be likened to a “burning, stabbing, or gnawing sensation”. Less commonly, you may also experience a deep, aching pain. 

Increased sensitivity of skin. Oftentimes, even the slightest touch of the affected part of your skin becomes unbearable if you have PHN. For example, you may experience pain even from the contact of a gentle breeze against your skin. 

What are the causes and risk factors of PHN?

PHN occurs when nerves in your body are damaged due to a shingles infection. As a result, this prevents your nerves from being able to properly send messages from the skin to the brain. Instead, the nerves send confused and random messages, resulting in chronic and intense pain in the areas affected. 

The biggest risk factor of PHN is age. Research has shown how the risk of developing PHN after a shingles infection increases from 15.7% to 32% from individuals between the age of 50 and 90 [3]. 

Other risk factors of PHN include medical conditions such as [3]: 

  • Diabetes mellitus
  • Chronic obstructive pulmonary disease (COPD) 
    • COPD is a type of chronic, inflammatory lung disease that results in long-term breathing problems and obstructed airflow to the lungs
  • Heart failure

How is PHN being diagnosed?

Although shingles is generally easy to recognise, PHN may be more difficult to diagnose as individuals experiencing pain long after their shingles rashes have cleared up may not be able to remember the rash and its location, or associate their current pain with it. However, there are several ways in which your doctor can diagnose your PHN.

When visiting a doctor, your doctor will most likely conduct a thorough medical examination before definitively diagnosing you with PHN, during which your doctor will likely conduct a physical examination and ask you about your medical history. 

How do I prevent myself from getting PHN?

The best prevention against PHN is to vaccinate yourself against shingles. Vaccination against shingles is especially recommended for patients over the age of 55. 

How is PHN treated?

PHN is often treated with medications. Some of these medications include: 

  • Anti-seizure medications
  • Antiviral agents
  • Antidepressants

Your doctor may also prescribe you painkillers to help relieve the pain. 

If you think that you may be experiencing postherpetic neuralgia, visit a doctor and seek medical attention immediately. 

References
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  1. Opstelten, W., W Mauritz, J., J de Wit, N., JM van Wijck, A., AB Stalman, W., & A van Essen, G. (2002). Herpes zoster and postherpetic neuralgia: incidence and risk indicators using a general practice research database. Family Practice, Volume 19(Issue 5), Pages 471–475,. https://doi.org/10.1093/fampra/19.5.471
  2. Saguil, A., Kane, S. F., Mercado, M. G., & Lauters, R. (2017). Herpes Zoster and Postherpetic Neuralgia: Prevention and Management. American Family Physician, 96(10), 656–663. https://www.aafp.org/afp/2017/1115/p656.html
  3. Muñoz-Quiles, C., López-Lacort, M., Orrico-Sánchez, A., & Díez-Domingo, J. (2018). Impact of postherpetic neuralgia: A six year population-based analysis on people aged 50 years or older. Journal of Infection, 77(2), 131–136. https://doi.org/10.1016/j.jinf.2018.04.004 
  4. Schug, S. A., & Arshad, A. A. M. (2016). Postherpetic neuralgia: how to prevent it, how to treat it. Medicine Today, 17(4), 23–29. https://medicinetoday.com.au/2016/april/feature-article/postherpetic-neuralgia-how-prevent-it-how-treat-it 
  5. McElveen, A. (2018). Postherpetic Neuralgia: Background, Pathophysiology, Epidemiology. EMedicine. https://emedicine.medscape.com/article/1143066-overview