A 3 year old child is seen by a pediatrician because he has developed multiple isolated lesions on his face and neck. Physical examination reveals many lesions up to 4 cm in diameter with golden crusts, while in other sites small blisters and weeping areas are seen. Which of the following is the most likely diagnosis?
Aphthous ulcers
Erysipelas
Herpes simplex I
Impetigo
This is impetigo, which is typically seen in preschool children with poor hygiene, paicularly in the summer in warm climates. The characteristic lesion has a large golden crust. Most cases are caused by Staphylococcus aureus; Streptococcus pyogenes is occasionally implicated. Impetigo is highly infectious, and mini-epidemics can occur in daycare settings. The initial treatment is typically with penicillins and topical preparations. Methicillin-resistant strains are presently rare in this setting, but can occur. Aphthous ulcers commonly known as "canker sores," are painful, shallow ulcers of the oral cavity. Erysipelas is a different type of skin infection, often caused by Streptococcus pyogenes (also sometimes others including Staphylococcus), and is characterized by large erythematous patches. Herpes simplex I causes tiny oral and perioral vesicles, but not large golden crusts. Ref: Morelli J.G., Prok L.D. (2012). Chapter 15. Skin. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.