Impetigo is a common and highly contagious skin infection that causes sores and blisters. It's not usually serious and often improves within a week of treatment or within a few weeks without treatment.
Impetigo is the most common skin infection in young children in the UK, but it can affect people of all ages.
This topic covers:
When to seek medical advice
Preventing the spread of impetigo
Preventing recurrent impetigo
Symptoms of impetigo
There are two types of impetigo:
- non-bullous impetigo – the most common type
- bullous impetigo
The symptoms of both types are described below.
The symptoms of non-bullous impetigo begin with the appearance of red sores – usually around the nose and mouth but other areas of the face and the limbs can also be affected.
The sores quickly burst leaving behind thick, golden crusts typically around 2cm across. The appearance of these crusts is sometimes likened to cornflakes stuck to the skin.
After the crusts dry, they leave a red mark that usually fades without scarring. The time it takes for the redness to disappear can vary between a few days and a few weeks.
The sores aren't painful, but they may be itchy. It's important not to touch or scratch the sores because this can spread the infection to other parts of the body, and to other people.
Other symptoms, such as a high temperature (fever) and swollen glands, are rare but can occur in more severe cases.
The symptoms of bullous impetigo begin with the appearance of fluid-filled blisters (bullae) which usually occur on the central part of the body between the waist and neck, or on the arms and legs. The blisters are usually about 1-2cm across.
The blisters may quickly spread, before bursting after several days to leave a yellow crust that usually heals without leaving any scarring.
The blisters may be painful and the area of skin surrounding them may be itchy. As with non-bullous impetigo, it's important not to touch or scratch the affected areas of the skin.
Symptoms of fever and swollen glands are more common in cases of bullous impetigo.
When to get professional advice
Impetigo isn't usually serious and can be treated by a pharmacist. Your pharmacist may recommend that you contact your GP practice if required.
Causes of impetigo
Impetigo occurs when the skin becomes infected with bacteria, usually either Staphylococcus aureus or Streptococcus pyogenes.
The bacteria can infect the skin in two main ways:
- through a break in otherwise healthy skin – such as a cut, insect bite or other injury – this is known as primary impetigo
- through skin damaged by another underlying skin condition, such as head lice, scabies or eczema – this is known as secondary impetigo
The bacteria can be spread easily through close contact with someone who has the infection, such as through direct physical contact, or by sharing towels or flannels.
As the condition doesn't cause any symptoms until four to 10 days after initial exposure to the bacteria, it's often easily spread to others unintentionally.
Children and people with diabetes or a weakened immune system – either due to a condition such as HIV or a treatment such as chemotherapy – are most at risk of developing impetigo.
Impetigo usually gets better without treatment in around two to three weeks.
However, treatment is often recommended because it can reduce the length of the illness to around seven to 10 days and can lower the risk of the infection being spread to others.
The main treatments prescribed are antibiotic creams or antibiotic tablets. These usually have to be used for around a week.
Read about treating impetigo.
Preventing the spread of impetigo
During treatment, it's important to take precautions to minimise the risk of impetigo spreading to other people or to other areas of the body.
Most people are no longer contagious after 48 hours of treatment or once their sores have dried and healed. It's important to stay away from work, school, nursery or playgroup until this point.
The advice below can also help to prevent the spread of the infection:
- don't share flannels, sheets or towels with anyone who has impetigo – wash them at a high temperature after use
- wash the sores with soap and water and cover them loosely with a gauze bandage or clothing
- avoid touching or scratching the sores, or letting others touch them – it may help to ensure your nails are kept clean and short
- avoid contact with newborn babies, preparing food, playing contact sports, or going to the gym – until the risk of infection has passed
- wash your hands frequently – particularly after touching infected skin
- washable toys should also be washed – wipe non-washable soft toys thoroughly with a cloth that has been wrung out in detergent and warm water and allowed to dry completely
If you think that the infection has spread to someone else, make sure they're seen by a pharmacist as soon as possible.
Preventing recurrent impetigo
To reduce the risk of impetigo returning, make sure any cuts, scratches or bites are kept clean. Ensure any condition that causes broken skin, such as eczema, is treated promptly.
If you develop impetigo frequently, your doctor may suggest taking a swab from around your nose to see if you carry staphylococcal bacteria. These bacteria can live in the noses of some people without causing problems, although they can lead to impetigo if they infect broken skin nearby.
If you're found to carry these bacteria, you may be prescribed an antiseptic nasal cream to apply several times a day for five to 10 days in an attempt to clear the bacteria and reduce the chances of impetigo recurring.
Complications of impetigo
Complications of impetigo are rare, but they can sometimes occur and can be serious. Tell your pharmacist if you have impetigo and your symptoms change or get worse.
Some complications associated with impetigo include:
- cellulitis – an infection of the deeper layers of the skin and underlying tissue
- scarlet fever – a rare bacterial infection that causes a fine, pink rash across the body
- guttate psoriasis – a non-infectious skin condition that can develop in children and teenagers after a bacterial infection
- septicaemia (a type of sepsis) – a bacterial infection of the blood
- Staphylococcal scalded skin syndrome (SSSS) – a serious skin condition that looks like the skin has been scalded with boiling water
- post-streptococcal glomerulonephritis – an infection of the small blood vessels in the kidneys
In very rare cases, impetigo may lead to some scarring, particularly if you scratch at the blisters, crusts or sores