What are the potential complications of chickenpox that I should monitor for in my patients?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

When monitoring patients with chickenpox, you should be aware of several potential complications:

  • Bacterial Superinfection: This is a common complication, affecting 32% of children and 17% of adults admitted to hospital with chickenpox in one UK study . Monitor for a sudden high-grade fever (pyrexia), especially after initial improvement, along with redness (erythema) and tenderness surrounding the original chickenpox lesions .
  • Dehydration: Encourage and monitor fluid intake . Advise patients to seek medical attention if signs of dehydration develop, such as reduced urine output, lethargy, cool peripheries, or reduced skin turgor .
  • Serious Complications: Less common but severe complications include pneumonia, encephalitis, and severe secondary bacterial infection of the skin . If these are suspected, the patient should be admitted to hospital .

Patients at increased risk of complications include:

  • Adults: Adults are more likely to develop complications than children .
  • Smokers and those with chronic conditions: People who smoke, have severe lung or cardiovascular disease, or a chronic skin disorder are particularly at risk .
  • Pregnant Women: Pregnant women are at higher risk of serious complications, such as fulminating varicella pneumonia, with the risk being greatest in the second and early third trimesters . There is also a small risk of fetal varicella syndrome if chickenpox develops in the first 28 weeks of pregnancy .
  • Immunocompromised Individuals: This includes people receiving cancer treatment, high doses of oral steroids, or those with conditions that reduce immunity .
  • Infants: Infants aged 4 weeks or less are also at increased risk .

It is important to advise patients to seek urgent medical advice if their condition deteriorates or if they develop any of these complications .

Educational content only. Always verify information and use clinical judgement.

What are the potential complications of chickenpox that I should monit