Impetigo is a superficial bacterial skin infection, usually caused by the staphylococcus aureus bacteria. A “golden crust” is characteristic of a staphylococcus skin infection. It is also less commonly caused by the streptococcus pyogenes bacteria. Impetigo is contagious and children should be kept off school during the infection.
Impetigo occurs when bacteria enter via a break in the skin. This may be in otherwise healthy skin or may be related to eczema or dermatitis.
Impetigo can be classified as non-bullous or bullous.
Non-bullous impetigo typically occurs around the nose or mouth. The exudate from the lesions dries to form a “golden crust”. They are often unsightly but do not usually cause systemic symptoms or make the person unwell.
Topical fusidic acid can be used to treat localised non-bullous impetigo. Draft NICE guidelines from August 2019 suggest using antiseptic cream (hydrogen peroxide 1% cream) first line rather than antibiotics for localised non-bullous impetigo.
Oral flucloxacillin is used to treat more wide spread or severe impetigo. Flucloxacillin is the antibiotic of choice for staphylococcal infections.
Advise about measure to avoid spreading the impetigo. Patients should be given advice about not touching or scratching the lesions, hand hygiene and avoiding sharing face towels and cutlery. They need to be off school until all the lesions have healed or they have been treated with antibiotics for at least 48 hours.
Bullous impetigo is always caused by the staphylococcus aureus bacteria. These bacteria can produce epidermolytic toxins that break down the proteins that hold skin cells together. This causes 1 – 2 cm fluid filled vesicles to form on the skin. These vesicles grow in size and then burst, forming a “golden crust”. Eventually they heal without scarring. These lesions can be painful and itchy.
This type of impetigo is more common in neonates and children under 2 years, however it can occur in older children and adults. It is more common for patients to have systemic symptoms. They may be feverish and generally unwell. In severe infections when the lesions are widespread, it is called staphylococcus scalded skin syndrome.
Swabs of the vesicles can confirm the diagnosis, bacteria and antibiotic sensitivities. Treatment of bullous impetigo is with antibiotics, usually flucloxacillin. This may be given orally or intravenously if they are very unwell or at risk of complications. The condition is very contagious and patients should be isolated where possible.
Impetigo usually responds well to treatment without any long term adverse effects. Rarely there can be complications:
- Cellulitis if the infection gets deeper in the skin
- Post streptococcal glomerulonephritis
- Staphylococcus scalded skin syndrome
- Scarlet fever
Last updated January 2020