Chickenpox (also known as varicella) is a common contagious disease in children. It is characterized by an itchy blister-like rash that appears 10 to 21 days after exposure to or contact with an infected person. Prior to the onset of the blisters, the first noticeable symptoms usually include a fever, headache, and a feeling of general discomfort.
Scratching the blisters can sometimes cause a bacterial infection.
Once the symptoms go away, the chickenpox virus stays in the body and remains dormant. Occasionally, it is reactivated years later, causing shingles (painful lesions).
Causes and triggers
Chickenpox is caused by a virus that is spread by contact with an infected person through secretions or respiratory droplets. A person is contagious 2 days before symptoms appear and until the blisters crust over.
In children, chickenpox is usually a benign illness. However, it can be more severe in adults and people with weakened immune systems. These groups are also more likely to develop certain complications, including:
- Otitis (ear infection)
- Pneumonia (lung infection)
- Encephalitis (brain inflammation)
The rash usually crusts over within 7 days and resolves on its own 1 to 2 weeks later. To manage fever and pain, the use of acetaminophen (e.g., Tylenol) is recommended. The following measures may also help reduce related itchiness:
- Take antihistamines (e.g., Benadryl, Reactine).
- Add baking soda (½ cup) or colloidal oat powder (e.g., Aveeno) to bath water.
- Apply calamine lotion.
Medications are available to treat the virus. While healthy individuals do not usually need this medication, it can be prescribed to those at risk of developing a more serious illness.
Individuals who are contagious should avoid public places in order to avoid exposing vulnerable individuals to the virus.
To prevent bacterial skin infections, keep the skin clean and avoid scratching. Handwashing with soap and keeping fingernails short is recommended.
The best way to prevent chickenpox is through vaccination. Children and adults who have never had chickenpox and who have not been vaccinated should get then chickenpox vaccine.
When should I see a medical professional?
Contact a medical professional if chickenpox is suspected, and if:
- You are pregnant.
- You or your child have a weakened immune system.
- You or your child develop a new fever (fever goes away then comes back a few days later).
- Your child does not want to play, eat or drink (especially if they have a high fever or blisters in their mouth).
- One or more of the blisters becomes swollen, red or very sore.
For more information:
Canadian Paediatric Society