What are the symptoms of chicken pox and how is it treated?

Chickenpox: Clinical Presentation and Management

Primary Symptoms

Chickenpox presents as a characteristic pruritic vesicular rash that appears in successive crops over 3 days, accompanied by fever and constitutional symptoms lasting approximately 5 days. 1

Classic Rash Characteristics

• Lesions progress through distinct stages: macules → papules → vesicles → pustules → crusts 1
• Vesicles are fragile, superficial, and surrounded by erythematous halos 2
• Distribution is centripetal: concentrated on trunk, back, chest, face, and head more than extremities 1, 3
• Typical lesion count: 250-500 skin lesions in wild-type disease 1
• Mucosal involvement: lesions frequently develop in mouth, conjunctivae, or other mucosal sites 1

Constitutional Symptoms

• Fever (though not universal in all cases) 1
• Malaise and fatigue 1
• Headache 4
• Throat pain 4
• Cough and respiratory symptoms (may herald pneumonia) 4

Timing and Contagiousness

• Incubation period: 14-16 days (range: 10-21 days) 1
• Contagious period: 1-2 days before rash onset until all lesions are crusted 1
• Disease duration: fever and rash last approximately 5 days 1

Laboratory Findings

Common nonspecific laboratory abnormalities include leukopenia, thrombocytopenia, and elevated transaminases. 2

• Thrombocytopenia: occurs in 42.1% of hospitalized adults 4
• Elevated ALT: occurs in 51.9% of cases, with >10-fold elevation in 4.9% 4
• ESR is not highly elevated in uncomplicated chickenpox 2

Complications by Population

Adults and Adolescents (Higher Risk)

Adults experience significantly more severe disease than children, with higher rates of complications and mortality. 1, 5, 6

Most common adult complications:

• Varicella pneumonia: 28.4% of hospitalized adults, with 17.2% mortality rate 4
• Bacterial skin superinfection: 25.4% 4
• Hepatitis: elevated transaminases in >50% 4
• Septicemia: 10.7% 4
• Encephalitis/meningitis: 8.8% 4
• ARDS: 6.8% 4
• Acute renal failure: 2.9% 4

Risk factors for severe pneumonia:

• Male sex 4
• Older age (p<0.005) 4
• Smoking (p<0.002) 4
• Presence of respiratory symptoms (p<0.0001) 4

Immunocompromised Patients

Chickenpox in immunocompromised individuals is potentially fatal and requires immediate intravenous acyclovir. 5, 6

• Visceral dissemination can involve lungs, liver, and brain 3
• High morbidity and mortality rates 3

Secondary Household Cases

Secondary cases in family settings are typically more severe than primary cases due to higher viral inoculum from intense exposure. 1

Treatment Algorithm

Immunocompetent Children

For otherwise healthy children, oral acyclovir 20 mg/kg per dose (maximum 800 mg) four times daily for 5 days should be initiated within 24 hours of rash onset. 7, 5

• Treatment indication: secondary/tertiary household cases (more severe disease expected) 5
• Timing is critical: efficacy established only when started within 24 hours of rash 7
• Benefits: reduces duration of fever, constitutional illness, and time to cutaneous healing 5

Adolescents and Adults

All adolescents and adults with chickenpox should receive oral acyclovir 800 mg five times daily for 5 days, initiated within 24 hours of rash onset. 7, 5, 6

Immunocompromised Patients

Intravenous acyclovir must be initiated immediately upon recognition of chickenpox in immunocompromised hosts. 5, 6

• Do not wait for laboratory confirmation 6
• IV route is mandatory (oral insufficient for this population) 7

Pregnant Women

Pregnant women with chickenpox require specialist evaluation and consideration for antiviral therapy. 6

• Risk of fetal vaccinia if infection occurs during pregnancy 1
• Acyclovir is Pregnancy Category B: use only if potential benefit justifies risk 7

Post-Exposure Prophylaxis

Vaccination

Varicella vaccine administered within 3 days of exposure is >90% effective in preventing disease; within 5 days it is 70% effective in preventing disease and 100% effective in modifying severe disease. 8

• Household contacts have highest risk: 85% attack rate (range 65-100%) 8
• Dosing for children 12 months-12 years: two 0.5-mL doses subcutaneously, separated by at least 3 months 8

Varicella-Zoster Immune Globulin (VZIG)

VZIG is reserved for high-risk exposed individuals without immunity: immunocompromised patients, neonates with specific maternal exposure timing, and premature infants—NOT healthy children. 8

Critical Pitfalls to Avoid

• Never delay treatment waiting for laboratory confirmation in suspected cases 6
• Do not initiate treatment >24 hours after rash onset in immunocompetent patients (efficacy not established) 7
• Avoid salicylates for 6 weeks after varicella vaccination due to Reye syndrome risk 8
• Ensure adequate hydration during acyclovir therapy to prevent renal dysfunction 7
• Adjust dosing for renal impairment according to creatinine clearance 7
• Recognize that chickenpox does NOT protect against future transmission: patients should avoid contact with lesions even after recovery, as asymptomatic viral shedding can occur 7