Chickenpox in Babies UK: Symptoms, Home Management, and When to Seek Help

Chickenpox is one of the most common childhood infections in the UK, and most children will encounter it at some point. For the majority, it is an unpleasant but uncomplicated illness. However, there are specific circumstances — particularly in very young babies — where chickenpox carries real risk. This guide explains what to expect, how to manage it at home, and when the situation requires medical attention.

What Is Chickenpox?

Chickenpox (varicella) is caused by the varicella-zoster virus. It is highly contagious, spreading through respiratory droplets and direct contact with the fluid in chickenpox blisters. A child with chickenpox is contagious from about two days before the rash appears until all the blisters have dried and crusted over — usually five to seven days after the rash first appears.

The incubation period is 10 to 21 days from exposure to the first symptoms.

What Chickenpox Looks Like

The illness typically begins with:

• A fever, loss of appetite, and feeling generally unwell
• After one to two days, an itchy rash appears

The rash starts as small red spots that rapidly develop into fluid-filled blisters (vesicles). These blister, burst, and crust over within a few days. New crops of spots appear over several days, so children often have spots at all stages simultaneously — fresh red spots, blisters, and crusted scabs all at the same time.

The rash appears most commonly on the trunk, scalp, and face, but can spread to cover the entire body including the mouth, inside the ears, and genitals. Spots on mucous membranes can be more painful than those on the skin.

Home Management

For healthy children over one year old, chickenpox is generally managed at home:

Relieve itching. Itching is the primary source of discomfort. Options include:

• Cool baths (with or without colloidal oatmeal — available in pharmacy products such as Oilatum)
• Calamine lotion applied to individual spots
• Non-sedating antihistamines (such as cetirizine) — check age guidance; some antihistamines are not suitable for young children
• Cool, damp cloths applied to itchy areas
• Keeping nails short to reduce damage from scratching, and in babies, scratch mitts

Manage fever. Paracetamol (such as Calpol) is appropriate for fever and discomfort. Use the correct dose for the child's weight and age.

Do not use ibuprofen. This is important: ibuprofen is specifically not recommended for chickenpox, as it has been associated with an increased risk of serious secondary bacterial skin infections (necrotising fasciitis) in children with chickenpox. Use paracetamol only.

Do not use aspirin. Aspirin is contraindicated in children under sixteen years.

Keep the child well hydrated. Offer frequent drinks. If mouth ulcers from the rash are making drinking painful, ice lollies or cold drinks can help.

Comfort. Keep clothing loose and soft. Keep the environment cool rather than warm — heat worsens itching.

When Chickenpox Is Dangerous

Babies Under Four Weeks Old

Neonatal chickenpox — in babies under 28 days old — is a medical emergency. Newborns have immature immune systems and have had little time to accumulate maternal antibodies against varicella. Chickenpox in a neonate can cause severe disease affecting the lungs, liver, and brain, with significant mortality.

If a newborn is exposed to chickenpox, contact the GP or hospital immediately. Treatment with varicella-zoster immunoglobulin (VZIG) is available as post-exposure prophylaxis for newborns of non-immune mothers, and antiviral treatment with aciclovir is given if the baby develops symptoms.

Babies of Non-Immune Pregnant Women

If a pregnant woman who has never had chickenpox or been vaccinated is exposed to varicella, she should seek medical advice urgently. Chickenpox in pregnancy can cause serious maternal illness and, depending on the timing, can cause foetal varicella syndrome or neonatal chickenpox.

Immunocompromised Babies and Children

Children who are immunosuppressed — due to cancer treatment, high-dose steroids, primary immunodeficiency, or other conditions — are at serious risk from chickenpox. Contact the treating team or emergency services if an immunocompromised child is exposed to or develops chickenpox.

When to Seek Medical Help During Chickenpox

Contact your GP or call 111 if your baby or child with chickenpox:

• Is under one month old
• Has a very high fever (above 39.5°C) that is not controlled by paracetamol, or a fever that returns after initially improving
• Has spots that appear very red, hot, swollen, or weepy — this may indicate a secondary bacterial skin infection
• Develops a severe headache, neck stiffness, sensitivity to light, or altered consciousness
• Has breathing difficulties or a new, significant cough
• Is vomiting repeatedly
• Has spots in the eye
• Seems significantly more unwell than you would expect, or your instinct says something is wrong

Call 999 or go to A&E for:

• Difficulty breathing
• A child who seems very ill, is floppy, or is difficult to rouse
• A newborn or very young baby with any chickenpox symptoms

The Varicella Vaccine: Not on the UK Schedule

The varicella vaccine is routinely given to children in many countries — including the United States, Germany, and Australia — as part of the national immunisation programme. However, it is not on the UK NHS childhood immunisation schedule for routine use in healthy children.

The NHS position is that universal vaccination could paradoxically increase the risk of shingles in adults in the short to medium term, because exposure to circulating chickenpox in the community helps maintain adults' immunity to varicella-zoster (which prevents reactivation as shingles). Removing community circulation through vaccination could reduce this "natural boosting" effect.

The varicella vaccine is, however, available privately in the UK for families who wish to vaccinate their children outside the NHS schedule. It is also offered on the NHS to healthcare workers who are not immune to varicella.

If your child has a condition that makes chickenpox particularly dangerous, discuss vaccination options with your GP or specialist.