Chickenpox
Chickenpox, caused by the varicella-zoster virus, is a highly contagious viral infection primarily affecting children, although adults and immunocompromised individuals can also contract it. It spreads through airborne transmission and can be characterized by symptoms resembling a cold initially, such as fever, sore throat, and malaise, followed by a distinctive itchy rash that forms red spots and blisters. The disease is usually self-limiting, resolving in about two to three weeks, although complications like bacterial skin infections and pneumonia can occur, particularly in high-risk populations.
The introduction of the varicella vaccine in 1995 has significantly reduced the incidence of chickenpox, leading to a 90% decline in cases over a decade. The vaccine is highly effective, preventing most cases and resulting in milder symptoms for vaccinated individuals who still contract the virus. While treatment focuses on symptom relief, including antihistamines and topical treatments for itchiness, antiviral medications may be utilized for those at higher risk of severe complications. Understanding chickenpox is essential, especially in light of historical treatment developments and the importance of vaccination in public health.
Chickenpox
Also known as: Varicella
Anatomy or system affected: Skin, mouth, nose
Definition: A highly infectious viral disease occurring primarily in children. Chickenpox is characterized by weakness, fever, and a generalized body rash.
Causes: Varicella-zoster virus (VZV) infection
Symptoms: Generalized body rash, intense itching, malaise, weakness, fever, sore throat, runny nose
Duration: Two to three weeks
Treatments: None; alleviation of symptoms
Causes and Symptoms
Chickenpox is an acute, highly contagious viral disease occurring primarily, but not exclusively, in children. Prior to the introduction of the varicella-zoster virus vaccine in 1995, there were about four million cases reported in the United States each year, with the highest incidence occurring during the late winter and early spring. About ten thousand people who contracted chickenpox became so ill that they required hospitalization and approximately 100 to 150 people died of chickenpox each year. However, since the introduction of the varicella-zoster virus vaccine, the number of cases and the number of hospitalizations have dropped significantly. In the ten years after the introduction of the vaccine, from 1995 to 2005, varicella disease incidence declined approximately 90 percent.
The varicella-zoster virus (VZV) is responsible for chickenpox infection. Physical contact with an infected individual is not required, as the virus is transmitted from person to person via an airborne route.
Symptoms typically begin to appear about fourteen to sixteen days after exposure. At first, they may resemble those of the common cold: sore throat, runny nose, malaise, and fever. Soon, red spots appear on the body, usually beginning on the trunk and scalp and spreading outward. Occasionally, the mucous membranes are affected as well, with spots appearing in the mouth and nasal passages. The spots develop into vesicles—raised bumps with clear, teardrop-shaped blisters that turn rapidly to crusty lesions within six to eight hours. The rash occurs in waves, with new spots developing as old ones heal and disappear. By the fifth or sixth day, no new lesions will develop, and the crusts will be gone in less than twenty days.
Chickenpox causes intense itchiness. The impulse to scratch can be overwhelming and can lead to one of the most common complications: bacterial skin infections, such as cellulitis. Scratching the lesions can also lead to pox scarring. Other possible complications of chickenpox include pneumonia; infections such as invasive group A streptococcal, sepsis, and necrotizing fasciitis; Reye syndrome; and encephalitis.
The diagnosis of chickenpox is almost always done on the basis of its symptoms, most notably its characteristic rash accompanied by fever. In the event that confirmation of the disease is necessary, the fluid in the lesions can be cultured, although by the time results are obtained (five to ten days), the disease is usually on its way to resolution.
Treatment and Therapy
In children, chickenpox, uncomfortable although it may be, is a self-limited disease in most patients. The vast majority of cases are uncomplicated and resolve themselves within two to three weeks. Treatment is therefore primarily symptomatic, with an emphasis on controlling itching and reducing fever.
Oral antihistamines such as Benadryl (diphenhydramine) and Atarax (hydroxyzine) are effective in managing pruritus. Topical treatments, such as calamine lotion, and wet compresses may offer almost immediate relief. Fever is treated with acetaminophen or ibuprofen. Aspirin is not an option because of its link to Reye’s syndrome, a potentially fatal condition characterized by vomiting, disorientation, and eventual coma. Fluids and electrolytes should be given frequently to prevent dehydration.
Some parents trim short the fingernails of infected children to keep them from scratching away the crusts of chickenpox lesions. This is one way of reducing the risk of secondary bacterial infections. Frequent bathing is also helpful in preventing this complication.
Although there is no cure for chickenpox, the oral antiviral drugs acyclovir, valacyclovir, and famciclovir have been shown to be effective in decreasing the intensity of itching, hastening the healing of skin lesions, and generally shortening the duration of the disease. To be effective, treatment must begin within twenty-four hours of the appearance of the rash.
The use of acyclovir is not recommended for most children because of the relatively benign nature of the disease in this age group. However, for some high-risk children, such as premature infants, therapy should be started within twenty-four hours of the onset of illness. In adolescents older than age thirteen, adults, pregnant women, and immunocompromised individuals, however, chickenpox may have severe complications, and this increased risk may be lessened with acyclovir therapy. The mortality rate of chickenpox is as high as 7 percent among immunosuppressed patients.
Perspective and Prospects
Chickenpox has been around for so long that there are conflicting accounts about how it got its name. One theory has it that when chickenpox was first described, it was noted that its lesions looked as if they were placed upon the skin rather than arising from the skin itself. They were compared to chickpeas—hence the name. Another idea is that the term “chickenpox” was intended to distinguish this weaker pox illness from the more life-threatening smallpox—the term “chicken” being used, as in “chickenhearted,” to mean weak or timid.
Chickenpox was not considered a distinct rash disease until 1553, when the Italian physician Filippo Ingrassia differentiated it from scarlet fever. In 1785, the English physician William Heberden gave the earliest clear description of varicella, having distinguished it from smallpox in 1768. In 1924, T. M. Rivers and W. S. Tillett reported the isolation of the chickenpox virus.
Throughout history, the treatment of chickenpox has been symptomatic. In the 1970s, however, a vaccine became available for persons in high-risk categories. In 1995, a vaccine called Varivax was approved by the US Food and Drug Administration for use in children over the age of one. Initially a single dose, a second dose of the varicella vaccine was added in 2006, furthering increasing the vaccine's efficacy. Varivax is 90 percent effective in preventing chickenpox. Vaccinated individuals who still develop chickenpox get a milder form of the disease. The vaccine also protects individuals from developing shingles, an extremely painful rash that is caused by the varicella-zoster virus, which lies dormant in nerve tissue near the spinal cord and brain in individuals who have chickenpox and can be reactivated. Between 1995 and 2010, varicella cases in the United States declined 97 percent. According to the Centers for Disease Control and Prevention (CDC) in 2022, chickenpox has become rare in the United States, with only about 150,000 cases per year. Researchers estimate that the disease prevents 3.8 million cases annually.
Bibliography
"Chickenpox." MedlinePlus. US Dept. of Health and Human Services, 5 Apr. 2016. Web. 26 Apr. 2016.
"Chickenpox Now Rare in the U.S. Due to Routine Vaccination." Infectious Diseases Society of America (IDSA), 20 Oct. 2022, www.idsociety.org/news--publications-new/articles/2022/chickenpox-now-rare-in-u.s.-due-to-routine-vaccination. Accessed 1 Aug. 2023.
Gershon, Anne A., and Michael D. Gershon. "Pathogenesis and Current Approaches to Control of Varicella-Zoster Virus Infections." Clinical Microbiology Reviews 26.4 (2013): 728–43. Print.
Kiple, Kenneth F., ed. The Cambridge World History of Human Disease. New York: Cambridge University Press, 2008.
Kliegman, Robert M., et al., eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia: Saunders/Elsevier, 2015. Print
Kump, Theresa. “Chicken-Pox Survival Guide.” Parents 69.5 (May 1994): 29–31. Print.
Marquis, Julie. “Chickenpox Vaccine Is Swaying Skeptics.” Los Angeles Times. Los Angeles Times, 21 June 2000. Web. 13 Oct. 2013.
National Center for Immunization and Respiratory Diseases, Division of Viral Diseases. "Monitoring the Impact of Varicella Vaccination."Centers for Disease Control and Prevention, August 30, 2012.
"US Chickenpox Vaccination Program." Center for Disease Control and Prevention (CDC), 20 Oct. 2022, www.cdc.gov/chickenpox/vaccination-program-impact.html. Accessed 1 Aug. 2023.
"Varicella." Manual for the Surveillance of Vaccine-Preventable Diseases. US Dept. of Health and Human Services, 9 Nov. 2015. Web. 26 Apr. 2016.
"Varicella." Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Atlanta: Centers for Disease Control and Prevention, 2015. Print.
“Varicella (Chickenpox).” Conn’s Current Therapy. Ed Rick D. Kellerman, et al. Philadelphia: Saunders/Elsevier, 2012. Print.
Whitley, Richard J. “Varicella-Zoster Virus.” Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. Ed. Gerald L. Mandell, John F. Bennett, and Raphael Dolin. 7th ed. New York: Churchill Livingstone/Elsevier, 2010. Print.