6th July 2023

Impetigo

A common and contagious superficial skin infection often caused by Staphylococcus aureus, followed by Streptococcus pyogenes. Methicillin-resistant Staphylococcus aureus (MRSA) has been isolated in an increasing number of cases. Impetigo mostly affects children but can occur at any age. Atopic eczema, scabies and any type of skin trauma predisposes to impetigo. Impetigo presents on the face, extremities and flexural surfaces. It is itchy and may present with mild fever and lymphadenopathy. The 3 main types are shown in table 3:

Table 3: Types of impetigo

Impetigo on the chin

Image Source: Wikimedia Commons (2020). Impetigo2020, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Impetigo2020.jpg (Accessed on: 10 March 2022).

Impetigo is a clinical diagnosis. Bacterial swabs sent for MCS should be considered in persistent, recurrent and widespread cases. Patients should stay away from school/work until lesions dry out and scab over. Non-bullous impetigo is managed with a 5-day course of hydrogen peroxide 1% cream or topical fusidic acid 2% if not suitable. Bullous and more extensive impetigo require oral antibiotics for 5-7 days (e.g. flucloxacillin, clarithromycin).

Complications include cellulitis and SSSS. Rare complications like scarlet fever or glomerulonephritis can occur if the causative organism is group A beta-haemolytic streptococcus (Streptococcus pyogenes).