Impetigo: what are the symptoms, signs and treatment?

Impetigo is an unsightly skin infection that causes blisters and sores on the body and face. It lasts between a week and 10 days. Find out here what the symptoms are, how serious it is, who is most affected, and when to see a doctor.

What are the symptoms of impetigo?

Impetigo is a bacterial infection that causes red sores or blisters on the skin. It can affect any part of the body but is most commonly found on the face – especially around the nose and mouth – on the hands, and around the torso.

‘When the blisters burst they leave behind crusty golden-brown patches,’ says Dr Benjamin Dallyn, who works in Public Health Medicine in South London. ‘The sores often start around the hands or mouth, but they can occur anywhere on the body and they often spread. They might be itchy or painful.’

There are three types of impetigo: non-bullous, bullous and ecthyma

  • Non-bullous is the most common. It causes blisters that burst then form a yellow-gold crust – this is sometimes called a cornflake crust because it looks like cereal.
  • Bullous impetigo causes larger blisters than non-bullous ones that take longer to burst. These blisters start off clear then turn cloudy and are generally painless. They are particularly prevalent in pre-school children.
  • Ecthyma is also a non-bullous form of impetigo but it causes painful sores that go deeper into the skin layers and so are more likely to leave scars. As these sores heal they leave yellowish scabs surrounded by red skin.

What are the causes of impetigo?

‘Impetigo is a skin infection caused by a bacterium,’ explains Dr Dallyn. ‘The bacterium most commonly responsible is called Staphylococcus aureus. Aureus is Latin for gold, and the bacterium is so-named because it looks golden when grown in a lab.’

How does impetigo spread?

‘Impetigo is a very contagious infection that spreads through touch,’ says Dr Dallyn. ‘It usually starts on skin that is already damaged; for example, a graze or a patch of eczema. You can prevent this by making sure cuts and grazes are clean and covered, and by getting treatment for eczema.’

The bacteria that cause impetigo can also penetrate the skin via cold sores, chapped skin and insect bites.

To avoid catching impetigo don’t share bedlinen, clothes or towels with an infected person and wash these items at a high temperature after use. Try to prevent your child from itching the sores or blisters then touching another part of their body, as it also spreads this way.

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How to treat impetigo

Because impetigo is a bacterial infection it usually requires antibiotic treatment, either in the form of a cream or medicine.

Small patches tend to be treated with an ointment but if it has spread pills or liquid antibiotics will be needed.

The NHS website recommends that after starting antibiotic treatment impetigo will stop being contagious after a couple of days, or when the blisters have crusted over and dried out ­– whichever is sooner. Even if your child is showing signs of improvement they should complete the course of antibiotics.

When should I see a doctor about impetigo?

‘Always call your GP if you think your child has impetigo. They might ask you to bring your child in to be assessed, or they might give you advice over the telephone. They will usually treat it with antibiotic cream or tablets,’ advises Dr Dallyn, which will need to be prescribed by a health professional.

If the impetigo is very mild pharmacy chain Boots recommends washing the area with soap and water then leaving, uncovered, to let the patch dry up on its own, but because impetigo is so contagious and spreads easily doctors tend to prescribe a cream such as fusidic acid to halt the infection or in more severe cases oral antibiotics such as erythromycin or cephalexin.

These treatments are not available over the counter and milder antibiotic creams from chemists aren’t usually strong enough.

Occasionally, complications such as cellulitis – a more serious skin infection – can occur. ‘If the impetigo is not getting better after seven days of treatment, you should see your GP again,’ says Dr Dallyn.

What should I do if my baby gets impetigo?

Impetigo can be a threat to babies, in particular to newborns who don’t have the immunity to fight the infection. Take extra steps to avoid your baby catching it, and if they do see your GP as soon as possible. While the infection is manageable, if left untreated it can lead to more severe illnesses such as septicaemia, scarlet fever and kidney disorders, although these complications are rare.

You can help your baby by washing and disinfecting toys, bed linen, clothes and towels to prevent further contagion and by bathing your child in a mild disinfectant soap such as Savlon. Cut their fingernails short to stop them scratching the sores, which remain infectious while they ooze fluid. Wash your and their hands regularly, and keep them apart from other children in the household until the sores scab over.

What should I do if my child gets impetigo?

Because impetigo is so contagious keep your child off school or nursery until the sores are dry and have scabbed over, or until they’ve been on antibiotic treatment for a minimum of 48 hours. Keep their bedding and towels separate and both you and your child should wash your hands regularly to prevent further spreading.

Impetigo is usually more itchy and irritating than painful. To help make your child feel more comfortable dress them in loose, light clothing, keep the sores clean and dry (an antiseptic soap will do), and cut their fingernails short or – if you can – put them in mittens or gloves at night to prevent scratching.

‘Sometimes impetigo keeps coming back,’ says Dr Dallyn. ‘In this case, your GP might take a swab from the sore or from your child’s nose to check if a different antibiotic would be more effective.’

Can adults catch impetigo? If so what can I do if I catch impetigo while pregnant?

Children under the age of five are most prone to catching impetigo, although older kids and adults can be infected by it. This is especially true if they have a skin or immunodeficiency disorder, diabetes, or are having chemotherapy.

Pregnant women can catch it if they’re in close contact with someone who has it but because it’s a superficial skin infection it won’t harm a growing foetus.