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Referral and warning signs
When to refer
Refer to Hospital (HC4/H) if: Signs of complications (pneumonia - cough/dyspnea, encephalitis - altered consciousness/seizures), Severe disease, High-risk patient (immunocompromised, pregnant, neonate), Significant secondary bacterial infection.
Red flags
- Difficulty breathing / Cough / Chest pain.
- Altered mental status / Stiff neck / Seizures.
- High fever persisting beyond 4 days.
- Extensive hemorrhagic lesions.
- Signs of severe secondary bacterial infection (spreading redness/pain).
- Lesions in the eye.
- Neonate with varicella.
- Pregnant woman with varicella.
Signs and symptoms
- Incubation period: 10-21 days (average 14-16 days).
- Prodrome (1-2 days before rash, esp. in older children/adults): Mild fever, malaise, headache.
- Rash: Evolves rapidly through stages:
- - Macules (red spots) -> Papules (raised bumps) -> Vesicles ('dew drops on a rose petal' - small fluid-filled blisters on red base) -> Pustules -> Crusting/Scabbing.
- - Intense itching (pruritus).
- - Rash typically starts on trunk/scalp/face, then spreads centrifugally to limbs.
- - Lesions appear in successive 'crops' over several days, so different stages (macules, papules, vesicles, crusts) are present simultaneously ('polymorphic rash').
- - Lesions may occur on mucous membranes (mouth, conjunctiva, vagina).
- Low-grade fever usually present during rash.
- Patient contagious from 1-2 days before rash onset until all lesions have crusted over (usually ~5-7 days after rash onset).
Risk factors
- No prior infection or vaccination.
- Exposure to infected individual (highly contagious via respiratory droplets and direct contact with vesicle fluid).
- Immunocompromised state (higher risk of severe/complicated disease).
- Pregnancy (risk to mother and fetus/neonate).
- Adult age (tend to have more severe disease).
Diagnosis
Clinical assessment
Diagnosis usually based on characteristic clinical presentation: history of exposure (if known) and typical polymorphic, itchy, vesicular rash starting centrally.
Differential diagnosis
- Insect bites (often grouped, lack evolution through stages).
- Scabies (burrows, intense itching worse at night, different distribution).
- Impetigo (honey-coloured crusts).
- Drug eruptions.
- Hand, Foot, and Mouth Disease (vesicles mainly on hands/feet/mouth).
- Disseminated Herpes Simplex (in immunocompromised).
- Smallpox (eradicated - lesions all at same stage, centrifugal distribution).
- Monkeypox (lesions often larger, umbilicated, prominent lymphadenopathy).
Investigations
- Usually clinical diagnosis.
- Viral PCR or Direct Fluorescent Antibody (DFA) test on vesicle fluid/scraping (confirmatory, rarely needed for typical cases).
- Serology (VZV IgM/IgG) - useful for confirming immunity or recent infection.
Diagnostic criteria
Clinical diagnosis based on characteristic rash.
Management
Non-pharmacological management
- Symptomatic Relief:
- - Keep skin clean and cool.
- - Tepid baths (may add oatmeal colloid).
- - Calamine lotion or other anti-itch preparations applied topically. (LOC: HC2)
- - Keep fingernails short to minimize scratching/secondary infection.
- Isolation: Keep child home from school/daycare until all lesions crusted to prevent spread.
Pharmacological treatment
- Antipyretics: Paracetamol for fever. Avoid Aspirin in children/adolescents due to risk of Reye's syndrome.
- Antihistamines: Oral antihistamines (e.g., Chlorphenamine 1-2mg Q12H <5y; 4mg Q12H >5y/Adult) for itching. (LOC: HC2)
- Antiviral Therapy (Acyclovir): Consider ONLY for high-risk individuals or severe disease (start within 24-72h of rash onset for best effect). Not routinely recommended for healthy children.
- - Indications: Adults/Adolescents (>12y), Secondary household cases (often more severe), Chronic skin/lung disease, Patients on long-term salicylates or short-course/inhaled steroids, Immunocompromised, Neonates, Pregnant women (specialist consultation).
- - Dose (UCG for >12y/Adults): Acyclovir 800mg PO 5 times daily for 7 days. (LOC: HC4)
- - IV Acyclovir needed for severe complications (pneumonia, encephalitis) or severe immunocompromise.
- Antibiotics: ONLY if secondary bacterial infection of skin lesions develops (e.g., impetigo - treat with topical/oral anti-staphylococcal antibiotics like Cloxacillin/Flucloxacillin).
Monitoring
Monitor for signs of complications.
Complications
- Secondary bacterial skin infection (Staph aureus, Strep pyogenes) -> Impetigo, Cellulitis, Abscess, Necrotizing fasciitis (rare).
- Varicella Pneumonia (more common/severe in adults, smokers, pregnant women, immunocompromised).
- Neurological complications: Cerebellar ataxia (most common neuro complication in children, usually benign), Encephalitis, Meningitis, Transverse myelitis, Guillain-Barré syndrome.
- Hepatitis.
- Thrombocytopenia / Purpura fulminans.
- Reye's syndrome (if aspirin used).
- Severe/disseminated disease in immunocompromised.
- Congenital Varicella Syndrome (if infection in early pregnancy).
- Neonatal Varicella (if maternal infection near delivery).
Prevention
- Vaccination: Varicella vaccine (live attenuated) provides effective protection. Included in some national programs, available privately.
- Post-Exposure Prophylaxis (PEP):
- - Varicella Vaccine: Can prevent or modify illness if given within 3-5 days of exposure to susceptible individuals.
- - Varicella-Zoster Immunoglobulin (VZIG): For high-risk susceptible individuals exposed (immunocompromised, pregnant women, neonates). Given within 96h ideally (up to 10 days). Specialist use.
- Isolation of infected individuals.
Patient education
- Explanation of chickenpox as a contagious viral illness.
- Expected course (rash evolution, crusting).
- Symptomatic relief (calamine, cool baths, antihistamines).
- Importance of avoiding scratching.
- Isolation measures to prevent spread.
- When to seek medical review (signs of complications).
- Avoidance of aspirin.
Uganda-specific notes
Common childhood illness. Vaccination not part of routine EPI but available privately. Management mainly symptomatic. Acyclovir use limited to high-risk/severe cases due to cost/availability. Secondary bacterial skin infections common.
References
- Uganda Clinical Guidelines (UCG) 2023
Chapter 2, Section 2.3.2