You or your child should not usually need any medical tests to diagnose chickenpox. You can be pretty sure that it is chickenpox if there are the key symptoms of a mild fever followed by an itchy rash, blisters and scabs. Chickenpox is a common viral illness that can have serious complications so seek help if unsure of the diagnosis.

Chickenpox spots are usually distinctive enough to distinguish from other rashes, although occasionally they can be easily confused with other conditions that affect the skin, such as insect bites or scabies (a contagious skin condition that causes intense itching).

If you're still uncertain about what is causing the symptoms, see your doctor.

When to contact your doctor

See your doctor if you're not sure whether you or your child have chickenpox.

Contact your doctor urgently if you have been in contact with someone who has chickenpox or you have chickenpox symptoms and:

• you are pregnant
• you have a weakened immune system (the body's defence system)
• your baby is less than four weeks old

Chickenpox in these instances can cause serious complications if left untreated. It is essential to seek medical advice so that you can receive any necessary treatment.

• Contact your doctor if you have chickenpox and are breastfeeding. They can advise about whether you should continue breastfeeding your baby.

If you or your child are exposed to chicken pox

If you or your child are exposed to chicken pox, your doctor may order a test to see if you or they are already immune from chickenpox.

If you have had chickenpox in the past, then it is extremely unlikely that you will develop chickenpox for a second time. If you've never had chickenpox, or you're unsure whether you've had it, then you may need an immunity test. This is a blood test that checks whether you are producing the antibodies to the chickenpox virus.

If your blood test result shows that you have the antibodies, you'll be naturally protected from the virus. If you don't have the antibodies, then you'll need to be monitored closely to see if you develop chickenpox symptoms. A post-exposure vaccination can reduce the risk of developing chicken pox.