What is the pattern of fever in varicella (chickenpox)?

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From the Guidelines

The fever pattern in chickenpox typically begins 1-2 days before the rash appears and continues for the first few days of the illness, usually lasting for 3-5 days. The fever is usually a moderate fever ranging from 100-102°F (37.8-38.9°C), though it can sometimes reach higher temperatures of 103-105°F (39.4-40.6°C) in severe cases 1. According to the study published in MMWR Recommendations and Reports in 1999, varicella is usually a self-limited disease that lasts 4-5 days and is characterized by fever, malaise, and a generalized vesicular rash typically consisting of 250-500 lesions 1.

The fever generally follows a continuous pattern rather than coming and going in cycles. Fever reducers like acetaminophen (at appropriate age-based dosing) can be used to manage the fever, but aspirin should be avoided in children with chickenpox due to the risk of Reye's syndrome. The fever occurs as part of the body's immune response to the varicella-zoster virus infection, with inflammatory cytokines triggering the hypothalamus to raise the body's temperature setpoint.

Some key points to consider when managing fever in chickenpox include:

  • The incidence of fever is lower in immunized individuals who develop breakthrough varicella, as noted in the 2007 study published in Pediatrics 1.
  • If the fever persists beyond 5-7 days or returns after initially resolving, this may indicate a secondary bacterial infection of the skin lesions, which would require medical evaluation.
  • The study published in Pediatrics in 2007 also highlights the importance of varicella vaccination in reducing the incidence of varicella and its complications, including fever 1.

From the Research

Pattern of Fever in Chicken Pox

  • The pattern of fever in chicken pox is not explicitly described in the provided studies 2, 3, 4, 5.
  • However, it is mentioned that treatment with acyclovir can decrease the number of pox lesions and shorten the duration of new lesion formation, and children treated with acyclovir begin to feel better soon and had fewer systemic signs and symptoms of chickenpox, including fever 2.
  • The studies focus on the treatment and prevention of chicken pox, as well as the effects of antiviral therapy on the disease, but do not provide specific information on the pattern of fever in chicken pox 3, 4, 5.

Treatment and Prevention

  • Acyclovir is the drug of choice for varicella and herpes zoster, and its clinical impact is related directly to its use early in the clinical course and to the likely susceptibility of the patient to severe or life-threatening VZV infection 5.
  • Prophylactic intervention with varicella-zoster immunoglobulin early in the incubation period can prevent or attenuate the disease manifestations of varicella in susceptible contacts at high risk from this infection 4.
  • Oral aciclovir is only effective if begun within 24 hours of onset of rash, and is recommended for treatment of varicella in otherwise healthy adults and adolescents, but not for routine use in children under 13 years of age unless they are sibling contacts or have other medical conditions 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acyclovir in the treatment of chickenpox.

Pediatric nursing, 1992

Research

Chickenpox: treatment.

BMJ clinical evidence, 2015

Research

Antiviral therapy for varicella and herpes zoster.

Seminars in pediatric infectious diseases, 2002

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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