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Home Topics Infectious Diseases Infections A-Z Impetigo General information - Impetigo

General information - Impetigo

Impetigo is a bacterial infection of the skin. It is caused by the same bacteria that commonly cause sore throats (group A streptococci or Streptococcus pyogenes although it can also be caused by Staphylococcus aureus), or by mixtures of both organisms. The skin becomes infected after bacteria enter through a break in the skin, such as a cut or insect bite.


Impetigo is not usually a serious condition and can be treated using antibiotic cream or tablets, but it is very infectious.  It is spread easily through person-to-person contact, or by sharing towels, clothes and other similar items. Outbreaks of impetigo can occur in areas where there is close contact between people, for example in schools, nurseries or army barracks.

Anyone can develop impetigo, but it is more common in children because the infection spreads easily in schools and nurseries. Impetigo affects approximately 3% of 1-4 year olds and 2% of 5-14 year olds in the UK every year. More cases are reported in the summer months when the skin is more exposed to cuts, bites and other lesions, leaving it prone to infection.

Health protection advice

Impetigo is extremely infectious, but basic hygiene measures can reduce the chances of spreading the infection to other areas of skin and to other people.

  • The rash should be kept clean with soapy water and loosely covered, either with a gauze bandage or clothing
  • Avoid touching the rash, or letting other people touch it, as much as possible
  • Wash hands frequently, especially after touching the rash
  • Do not share flannels, sheets, towels with others. After using, these should be washed at a high temperature
  • Skin crusts should be removed before the application of ointments. Crusts may reappear
  • Avoid preparing food until at least 48 hours after starting treatment  
  • Keep fingernails short
  • Avoid contact with newborn babies until the sores have stopped blistering or crusting, or until 48 hours after starting treatment
  • Avoid close contact sports or going to the gym until crusting and blistering has stopped
  • Keep children with impetigo away from school or nursery until the sores have stopped blistering or crusting or until 48 hours after starting treatment
  • Healthcare workers should not have contact with patients and report to their Occupational Health department
  • To reduce the chance of catching impetigo, keep cuts and scratches clean and make sure that any conditions involving broken skin (such as eczema or nappy rash) are treated quickly.

Impetigo - the symptoms?

  • There are two types on impetigo symptoms; bullous and non-bullous. Non-bullous is the most common, accounting for up to 70% of cases.

Non-bullous impetigo

  • Begins with the appearance of red sores, usually around the nose and mouth
  • These sores burst quickly leaving yellow-brown golden crusts
  • The crusts then dry leaving a red mark that generally heals without scarring
  • The sores are not painful, but may be itchy. Other symptoms of infection, such as fever and swollen glands are rare, but they may occur in more severe cases.

Bullous impetigo

  • Begins with the appearance of fluid-filled blisters, usually on the trunk of the body or the arms or legs
  • The blisters quickly spread and then burst after several days, leaving a yellow crust
  • The crusts dry and heal without scarring
  • The blisters are not painful, but the area of skin around them may be itchy. Other symptoms, such as fever and swollen glands, are more common in bullous impetigo.


It is possible for the bacteria that cause impetigo to enter deeper into the body and cause further infection. Complications can include:

  • Cellulitis - when the impetigo infection spreads to deeper layers of skin
  • Lymphangitis - inflammation of the lymphatic vessels that carry lymph (water, electrolytes and proteins) from body tissue to the bloodstream
  • Guttate psoriasis - a non-infectious skin condition that can develop in children and teenagers after a bacterial infection. It causes small, droplet- shaped sores on the chest, arms, legs and scalp
  • Scarlet fever - a rare bacterial infection that causes a fine pink rash across the body
  • Septicaemia - a potentially life-threatening bacterial infection of the blood
  • Post-streptococcal glomerulonephritis - a very rare complication of impetigo that causes an infection of the small blood vessels in the kidneys.

Complications like these are very rare, but anyone with impetigo should stay alert for changing or worsening symptoms.

Impetigo - how do you catch it?

You catch impetigo by coming into contact with the bacteria that cause it. This is usually through direct contact with someone who is infected. You can also become infected by using towels, facecloths, clothes, or toys that have been used by someone who is infected.

There are two types of impetigo; primary and secondary:

  • Primary impetigo is impetigo affecting skin which is otherwise healthy - for example, bacteria may enter the skin through a small wound, such as a scratch and then start to multiply
  • Secondary impetigo is when another skin condition leads on to the infection. For example, if the skin is already damaged by eczema, it is easier for the bacteria to gain entry and cause impetigo.

Anyone can catch impetigo, but it is most common in children and babies and in crowded environments (e.g. schools, nurseries and army barracks).
Other risk factors include having diabetes, a weakened immune system and playing contact sports.

Impetigo - Diagnosis and Treatment

  • The characteristic skin lesions produced by impetigo usually makes it easy to diagnose. Occasionally, it may be necessary for your doctor to take a swab from the affected area for laboratory testing to make the diagnosis, particularly if the lesions are spreading despite treatment, or if there are complications, such as deeper spread.
  • Impetigo will normally clear up on its own after 2-3 weeks. However, more serious infections can occasionally develop, so individuals with symptoms should go to their GP to rule out other potentially more serious infections and to receive antibiotics to help clear the infection more quickly (usually in 7-10 days). This will also reduce the time during which the patient is infectious, so fewer people will catch impetigo from them.
  • Antibiotics are usually given as a cream. This should be applied to the affected area after the crusts have been cleaned off with warm soapy water. After applying the cream, you should wash your hands to avoid spreading the infection to other parts of your body, or to other people.
  • If the rash is more extensive or is spreading rapidly, oral antibiotics (tablets) may be given instead of, or as well as, a cream.
  • Impetigo is infectious as long as the blisters continue to produce fluid.
  • With treatment, impetigo stops being infectious after two days. Crusts can then re-appear, but children may return to school and adults to work.

The role of the Health Protection Agency

The Health Protection Agency provides advice to health professionals on controlling outbreaks of impetigo and managing cases, when necessary. In outbreak investigations, the agency works with local professionals to look for the source of the infection, so that we can help to prevent other people from becoming infected.
The HPA is an independent organisation, set up by the government to protect the public from the health effects of infectious diseases and other hazards to health. The agency identifies, researches and responds to these threats. It gives advice to the public on how to avoid harm, provides data and information to the government and advises people working in healthcare.

If you have concerns about your health contact NHS Direct on 0845 4647 or visit their website, or see your family doctor.

Reviewed: 23 February 2010