Impetigo: symptoms, treatment and how long it is contagious

The NHS says impetigo starts with red sores or blisters, though redness may be harder to see on brown and black skin. The sores or blisters quickly burst and often leave crusty, golden-brown patches that can look a bit like cornflakes stuck to the skin. The patches can get bigger, spread to other parts of the body, be itchy and are sometimes painful.

The sores commonly affect the face, around the nose and mouth, and the hands. The British Association of Dermatologists says it may cause tender swollen glands in the neck, but it is unusual to have a fever or feel very unwell.

The NHS describes bullous impetigo, where yellow liquid oozes from blisters and hardens to leave a scaly border around a scab. The British Association of Dermatologists says this is more common in people who have another skin condition, like eczema or psoriasis.

The NHS says a pharmacist or GP will check whether symptoms are caused by a more serious skin infection like cellulitis. If it is impetigo, they may prescribe hydrogen peroxide cream, or antibiotic cream or tablets. Babies and people with a weakened immune system may need antibiotic tablets. It is important to finish treatment even if the impetigo starts to clear up.

The British Association of Dermatologists says that hydrogen peroxide 1% cream is applied 2 to 3 times per day for 5 days if you are otherwise well. It says that if large areas are affected, an antibiotic cream such as fusidic acid 2% or mupirocin 2% can be used, and that antiseptics are better if you can use them because bacteria can be resistant to some antibiotics. Oral antibiotics are very rarely needed.

If impetigo keeps coming back, the NHS says a GP may take a swab from the skin and from inside the nose, and might prescribe an antiseptic body wash, nasal ointment or both.

The NHS says impetigo can easily be spread to other parts of your body or to other people through skin-to-skin contact, and by touching things that have been infected, like towels and bedding. It stops being contagious 48 hours after you start using hydrogen peroxide cream or antibiotics prescribed by a pharmacist or GP.

If you do not get treatment, the NHS says it can take between 7 and 21 days to stop being contagious, usually when all the patches heal, dry out and crust over. NICE Clinical Knowledge Summaries says it is usually self-limiting and heals in 7 to 21 days without treatment, but treatment may lead to quicker resolution and a shorter infective period.

• stay away from work, school or nursery until no longer contagious

• wash affected areas with soap and water and dry them thoroughly

• wash hands frequently, particularly before and after using antibiotic cream

• wash flannels, towels, sheets and pillowcases at a high temperature, and toys with detergent and warm water

• do not touch or scratch sores, which also helps stop scarring

• do not share flannels, towels, sheets or pillowcases, and do not prepare food for other people

• do not go to the gym or play contact sports such as football

• avoid close contact with children or people with diabetes or a weakened immune system

The British Association of Dermatologists says impetigo is the most common skin infection seen in young children in the UK and can spread rapidly through families and school classes. It says children should be kept off school or nursery until the affected areas have healed or 48 hours after starting antibiotic treatment.

The NHS says a pharmacist can give the same medicines as a GP for people with symptoms, including a child aged 12 months or over. See a GP if the child is aged 11 months or younger. Check with the GP surgery before you go in, as impetigo is very infectious and they may suggest a phone consultation.

The British Association of Dermatologists describes impetigo as a contagious bacterial infection of the surface of the skin, caused by Staphylococcus or Streptococcus bacteria. NICE Clinical Knowledge Summaries says non-bullous impetigo makes up 70% of cases, and impetigo caused by MRSA is becoming increasingly common.

The NHS says impetigo usually infects skin that is already damaged, for example by a minor injury such as a cut, scratch or insect bite, or by a skin condition. The British Association of Dermatologists adds cold sores, psoriasis and eczema, and says people with diabetes or low immunity are more susceptible and that it is more common in warm, humid weather. It is not inherited.

The NHS lists conditions that can look similar. See a pharmacist or GP if you are unsure.

The NHS says to see a GP if you or your child have symptoms of impetigo and any of the following.

• your child is aged 11 months or younger

• you are breastfeeding and the sores are on your breasts

• you have a weakened immune system, for example from chemotherapy

• you have had treatment but symptoms have changed or become worse

• you have had impetigo in the past year and it has come back

The sources read for this guide do not give pregnancy-specific advice for impetigo, other than the NHS saying to see a GP if you are breastfeeding and the sores are on your breasts. If you are pregnant and think you have impetigo, ask a pharmacist or GP which treatment is suitable.

On the NHS, a pharmacist can assess and treat many cases of impetigo, with a GP for babies, people with weakened immunity or complicated cases. Because impetigo is very infectious, ring ahead before attending a surgery. Private GP or dermatology appointments are also available, though they are rarely needed for a first, uncomplicated episode.