Impetigo

What is impetigo and what does it look like?

• Primary impetigo is when the infection affects healthy skin.
• Secondary impetigo is when the infection affects skin that is already 'broken' by another skin condition. For example, skin with eczema, psoriasis or a cut sometimes develops a secondary impetigo.

The picture show a typical small patch of primary impetigo on the chin of a child.

The rash typically appears 4-10 days after you have been infected with the bacteria. Small blisters develop at first. You may not see the blisters as they usually burst to leave scabby patches on the skin. Sometimes only one or two patches develop. They often look like moist, golden crusts stuck onto the skin. An area of redness (inflammation) may develop under each patch. Sometimes affected skin is just red and inflamed - especially if the 'crust' is picked or scratched off.

The face is the most common area affected but impetigo can occur on any part of the skin. Patches of impetigo vary in size, but are usually quite small - a centimetre or so to begin with. Smaller 'satellite' patches may develop around an existing patch and spread outwards.

Who gets impetigo?

Impetigo commonly occurs in children, but it can affect anyone at any age. It occurs more commonly in hot humid weather. It is contagious and sometimes outbreaks occur in families or in people who live in close communities such as army barracks.

You are more prone to develop impetigo if you play contact sports, have diabetes, or if you have a poor immune system. For example, if you are taking steroids or chemotherapy.

What is the treatment for impetigo?

There is a good chance that impetigo will clear without treatment after 2-3 weeks. However, treatment is usually advised as it is contagious, and severe infection sometimes develops.

An antibiotic cream used for 7-10 days is the usual treatment if there are only a few small patches of impetigo on the skin. The crusts should be cleaned off with warm soapy water before applying the cream. This allows the antibiotic to penetrate into the skin. Antibiotic liquid medicine or tablets may be prescribed in some situations. For example, if the rash is more widespread, or if you have a poor immune system, or if you are generally unwell with symptoms such as fever and swollen lymph glands.

As impetigo is contagious (which means it can be passed on by touching):

• Try not to touch patches of impetigo, and do not allow other children to touch them.
• Wash your hands after touching a patch of impetigo, and after applying antibiotic cream.
• Don't share towels, flannels, bathwater, etc, until the infection has gone.
• Children should be kept off school or nursery until there is no more blistering or crusting, or until 48 hours after antibiotic treatment has been started.

Some things to look out for

Another skin infection called cellulitis is sometimes mistaken for impetigo. Cellulitis is a 'deeper' skin infection. Normally, with cellulitis the area of skin affected is larger, the skin is red, swollen and tender, and there are not usually any blisters or crusts. Cellulitis usually needs prompt treatment. See separate leaflet called 'Cellulitis'. In particular, see a doctor urgently if cellulitis develops close to an eye.

A patch of impetigo on the face near to the mouth is sometimes confused with a cold sore. Cold sores are due to a virus infection, and tend to recur in the same place from time to time. See separate leaflet called 'Cold Sores'.