Snapshot A4-year-old girl complains of pruritus and a rash on her face for one day. In the next morning her mother notices weeping from the rash and brings her to the pediatrician. She is afebrile. On exam there are multiple vesicles and pustules with overlying honey-colored crust on the chin. There are no bullae. The physician warns that there is a chance that her kidneys may be affected after the infection. Introduction Clinical definition superficial contagious bacterial skin infection which can be divided into nonbullous impetigo (most common) which is caused by Staphylococcus aureus or group A streptococci bullous impetigo caused by Staphylococcus aureus toxin which is a localized form of staphylococcal scalded skin syndrome Epidemiology Incidence 20.5 per 1000 person-years most common bacterial skin infection in children 3rd most common skin disease in children highly contagious 70% of cases are nonbullous impetigo Demographics occurs commonly in children Most common pathogen Staphylococcus aureus group A streptococcus Most common location on face and arms Risk factors summer weather disruption of skin leading to secondary infection of nonbullous impetigo insect bites varicella atopic dermatitis immunocompromise Etiology Pathophysiology superficial skin blister ruptures and forms a crust nonbullous impetigo from host response to infection bullous impetigo caused by staphylococcal toxin Presentation Nonbullous impetigo physcal exam single red macule or papule → vesicle surrounded by erythema → honey-crusted pustules Bullous impetigo physical exam progression from vesicle → flaccid bullae without erythema → crusted erosion ruptured bullae with yellow collarette from crusts Studies Labs positive Gram stain positive superficial wound culture may aid in directing antibiotic therapy Differential Herpes simplex virus vesicles on erythematous base (bullous impetigo typically has no erythema) Pemphigus foliaceus erythema with scaling and crusting Treatment Medical topical antibiotics indication local involvement of disease medications mupirocin, retapamulin, or fusidic acid oral antibiotics indication widespread involvement of disease medications empiric treatment with cephalexin Complications Spread to other members of the family impetigo is highly contagious cover open skin lesions Acute post-streptococcal glomerulonephritis 1-5% of patients with nonbullous impetigo Prognosis survival with treatment very good