Bullous impetigo

Bullous impetigo is a superficial bacterial skin infection caused predominantly by Staphylococcus aureus, specifically strains that produce exfoliative toxins (mainly exfoliative toxin A and B). These toxins target desmoglein 1, a protein important for cell-to-cell adhesion in the upper layers of the skin, leading to the formation of characteristic fluid-filled blisters (bullae). Bullous impetigo is a common form of impetigo and is classified under the broader category of impetigo (ICD-10: L01.0). It primarily affects the skin, most commonly on the trunk, extremities, and intertriginous areas (skin folds). The hallmark clinical features include flaccid, thin-walled bullae filled with clear to yellowish fluid that rupture easily, leaving shallow erosions with a collarette of scale. Unlike non-bullous impetigo, a honey-colored crust is less prominent. The surrounding skin may appear erythematous. Lesions are generally not painful but may be mildly pruritic. The condition most commonly affects neonates and young children, though it can occur at any age. In neonates, it can be particularly concerning due to the risk of more widespread infection. Systemic symptoms such as fever are uncommon in localized disease but may occur in extensive cases. Treatment depends on the extent and severity of the infection. Localized bullous impetigo is typically managed with topical antibiotics such as mupirocin or fusidic acid. More widespread or severe cases may require oral antibiotics, commonly first-generation cephalosporins or penicillinase-resistant penicillins (such as dicloxacillin or flucloxacillin), given the staphylococcal etiology. In regions with high rates of methicillin-resistant Staphylococcus aureus (MRSA), antibiotic selection should be guided by local resistance patterns and culture results. Good hygiene practices, including regular handwashing and keeping affected areas clean, are important to prevent spread. The prognosis is generally excellent, with most cases resolving without scarring. Rare complications include cellulitis, lymphangitis, or post-streptococcal glomerulonephritis if co-infection with group A Streptococcus is present.

Common questions about Bullous impetigo