Impetigo is a superficial, contagious bacterial infection of the skin usually caused by Staphylococcus aureus and/or Streptococcus pyogenes.
It is most common in children aged 2-5 years, although individuals of any age can be affected by this bacterial condition. Recent studies indicate that 111 million children and up to 140 million people are affected at any given time in developed countries.
Clinically, there are two variants: non-bullous impetigo, which is more common and accounts for up to 70% of cases, and bullous impetigo, which is less common. Non-bullous impetigo is caused by S. aureus and group A Streptococcus ß-hemolyticus, and usually manifests as small intraepidermal blisters, which subsequently form yellow-brown crusty lesions around the face, especially the nose and mouth, but can appear anywhere on the body. The lesions are usually less than 2 cm in size, are painless or minimally painful and have no erythema or constitutional symptoms
More severe forms may be associated with pruritus, erythema, crusting erosions, fissures and odour. Bullous impetigo is caused by strains of S. aureus that produce exfoliative toxin A, a toxin that causes loss of cell adhesion in the superficial epidermal layers. Lesions are usually large, transparent, flaccid superficial blisters (bullae) before rupturing, leaving round erosions that crust over. Bullous impetigo usually occurs in intertriginous areas of the trunk and extremities.
Antibiotic treatment should be started as soon as possible due to the high contagiousness of the disease, the associated discomfort and the poor cosmetic appearance.
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