Chronic pain can affect up to 70% of those with herpes zoster. – Pharmacy and Therapeutics (1)
Chickenpox may lead to a lifelong latent infection with the Varicella Zoster Virus (VZV), a type of herpes virus.
When VZV is reactivated, it is called herpes zoster. This reactivation is painful and usually shows up as a band of blisters. The risk of VZV reactivation increases with age. A study published in April 2013 in the journal Pharmacy and Therapeutics (1) says up to 7 in 10 of those affected by herpes zoster will experience chronic pain.
Dr. Kenneth R. Cohen and colleagues wrote that “Herpes zoster develops when VZV is reactivated in the dorsal ganglia and migrates to adjacent sensory dermatomes, causing a rash. Following a course similar to that of chickenpox, the rash starts as maculopapular lesions, which evolve into vesicles and form scabs within 10 days. Complete healing of the vesicles may take up to 1 month. The course of the disease is usually accompanied by unilateral pain that follows a dermatome. This pain may precede the eruption and may persist for weeks or months. Because the development of herpes zoster is normally suppressed by the immune system, reactivation tends to occur in people whose immunity is weakened, such as older or immunocompromised individuals.” (1) Dr. Cohen is an Associate Professor of Pharmacy and Health Outcomes at Touro College of Pharmacy in New York, New York.
In other words, pain may last well after the signs of the VZV infection have healed.
“PHN is defined as herpes zoster pain that continues for more than 30 days after the onset of skin healing.” (1) In fact, “PHN is the most common and most distressing sequela [condition] of herpes zoster in patients with intact immune systems.” (1) Moreover, “PHN can affect [up to] 70% of herpes zoster patients, and the incidence increases with age.” Additionally, the rate of PHN is almost 30% higher in people older than age 50 compared with younger individuals.
It is interesting to note that caucasians seem to develop herpes zoster (and therefore PHN) more often than African Americans. “3.4% of Caucasian subjects developed herpes zoster compared with 1.4% of African-Americans.” (1)
Finally, authors noted that “several risk factors predispose individuals to develop PHN following an outbreak of herpes zoster.
These factors include advanced age, the severity of the acute rash, the presence of a prodrome (hyperesthesia, paresthesia, burning, and/or pruritus), and female sex.” (1)
These findings are important for individuals to remember since “each 10-year increment in age [is] associated with a proportional increase in the incidence of the disorder.” (1)
(1) Kenneth R. Cohen, PharmD, PhD, CGP, Rebecca L. Salbu, PharmD, CGP, Jerry Frank, MD, FAAFP, and Igor Israel, MD “Presentation and Management of Herpes Zoster (Shingles) in the Geriatric Population.” P T. 2013 Apr; 38(4): 217-224, 227