Chickenpox (varicella): symptoms, spread and treatment

Chickenpox is caused by the varicella-zoster virus. The NHS describes it as a common infection that spreads easily and mostly affects children. Most people have had it by adulthood, and having it usually leaves you with antibodies that prevent a second bout.

The virus is passed on by being in the same room as someone who has it, by touching items carrying fluid from the blisters, and, if you have never had chickenpox, from someone with shingles. The reverse does not happen: you cannot catch shingles from a person with chickenpox. That is because shingles is the same virus reactivating later in life after lying dormant in nerve tissue, as NHS inform explains.

The main symptom is an itchy, spotty rash that can appear anywhere on the body. Before or after the rash you might have a high temperature, aches and pains, and loss of appetite. NHS inform notes that the fever and general illness tend to be more common and worse in adults than in children.

The NHS describes three overlapping stages. First, small spots appear, including inside the mouth and around the genitals where they can be painful. They may be red or pink on lighter skin and are harder to see on brown and black skin, although you should be able to feel them. Second, the spots fill with fluid and become very itchy blisters that may burst. Third, they form scabs, some flaky and some leaking fluid. New spots can appear while older ones are crusting, so a child may show all stages at once.

There is no specific treatment for most people; care is about comfort. The NHS recommends plenty of fluids, with ice lollies if a child is reluctant to drink, paracetamol for pain and discomfort, cooling creams or gels from a pharmacy, and asking a pharmacist about antihistamine medicine for itching. Bathe in cool water, pat the skin dry rather than rubbing, and dress in loose clothes. Cutting fingernails and putting socks on hands at night reduces scratching, which can scar.

Two cautions matter. The NHS says not to use ibuprofen unless a doctor tells you to, because it may cause serious skin infections, and not to give aspirin to children under 16 years. The NHS also says anyone with chickenpox should stay off school, nursery or work until all the spots have formed a scab, which is usually 5 days after they first appeared.

NHS inform adds that adults with chickenpox may be helped by antiviral medicine if it is diagnosed early enough. The NHS says some people at risk of complications may be able to take medicine to prevent them, started within 24 hours of the spots appearing, which is why early contact with 111 or a GP matters for those groups.

Chickenpox is usually not serious, but the NHS lists situations in which to get help from NHS 111 now. Ring the GP surgery before attending and tell the receptionist you think it might be chickenpox, so you are not sat in a waiting room with vulnerable patients.

• Skin around blisters becomes red, hot or painful, which may suggest infection (redness is harder to see on brown or black skin).

• A child shows signs of dehydration, such as fewer wet nappies.

• You are more short of breath than usual, or have chest pain.

• You have been near someone with chickenpox and are pregnant or have a weakened immune system.

• You think a newborn baby has chickenpox or has been in contact with it.

• A child under 5 needs advice, or you are breastfeeding and have symptoms.

• Call 999 or go to A&E if someone is very drowsy, confused, struggling to breathe or becoming rapidly worse.

NHS inform says chickenpox occurs in approximately 3 in every 1,000 pregnancies. Pregnancy slightly raises the risk of pneumonia, particularly later in pregnancy and in smokers. If infection happens in the first 28 weeks there is a small but significant risk of foetal varicella syndrome, which it describes as rare and potentially involving scarring, eye defects such as cataracts, shortened limbs and brain damage. Infection after week 20 can carry a risk of premature birth, and infection 7 days before or after delivery can cause a more serious illness in the newborn.

For that reason, NHS inform advises pregnant women, newborn babies and people with a weakened immune system who are exposed to the virus to speak to their GP as soon as possible. A blood test may be used to check whether you are already immune. Anyone being treated for cancer or taking steroid tablets is among those it names as at risk.

The NHS says children are now offered the MMRV vaccine, which protects against measles, mumps, rubella and chickenpox. Two doses are offered at 12 months and 18 months old, and older children born on or after 1 January 2020 are also offered one or two doses. Adults and children outside the programme may be vaccinated on the NHS if they could pass the virus to someone with a weakened immune system, for example if they live with a person receiving chemotherapy.

The most useful everyday precaution during an infection is isolation from vulnerable people. Keep to the NHS advice to stay away from newborn babies, pregnant women and anyone with weakened immunity until the spots have scabbed. Those with questions about private vaccination can discuss availability and cost with a private GP or travel clinic.

Most cases are managed without any appointment. The NHS website, a pharmacist and NHS 111 cover the common questions, and a GP is for those who are unsure of the diagnosis or are breastfeeding with symptoms. Adults who are otherwise well but feel very unwell can be seen by a GP for an antiviral decision, ideally in the first day.

Private care is rarely needed. A private GP appointment may be convenient for adults who want an early assessment, or for travellers who are unsure of their immunity, but the same red-flag advice and the same exclusion rules apply.