Impetigo is a contagious bacterial skin infection, most often seen in young children, that causes sores and blisters. When treatment begins, people often worry that the lesions appear to be worsening instead of improving. The visual progression of impetigo during healing can look alarming, but this is often a normal part of the skin’s recovery process. This article clarifies the typical course of the infection and explains why the appearance of the sores can sometimes intensify before they resolve.
Understanding Impetigo
Impetigo is primarily caused by two types of bacteria: Staphylococcus aureus or Streptococcus pyogenes. S. aureus is the most common cause. This infection affects the superficial layers of the skin (the epidermis) and often takes hold after the skin barrier has been compromised by a cut, scrape, or insect bite.
There are two main forms of the infection, which present differently. Non-bullous impetigo is the most common, accounting for approximately 70% of cases. This type initially presents as small, red sores that quickly burst and ooze fluid. Bullous impetigo is the less common form, caused almost exclusively by toxin-producing strains of S. aureus. This type is characterized by larger, fluid-filled blisters (bullae) that often appear on otherwise unbroken skin.
The Healing Trajectory: Why Lesions May Appear Messier
The perception that impetigo worsens before it improves is due to the visual transformation of the non-bullous sores as they begin to dry out. When the initial small blisters or pustules rupture, they release a purulent exudate. As this fluid dries, it mixes with bacteria and forms a thick, adherent layer over the wound.
This characteristic crust is often described as golden or honey-colored and can look like cornflakes stuck to the skin. While the appearance of this thick, golden crust may seem more severe than the initial small blister, its formation is a positive indicator that the infection is receding. The crust serves as a natural, protective dressing over the healing tissue.
The crusting phase represents the successful containment of the bacterial infection by the immune response and antibiotic treatment. As the skin regenerates new epidermal cells, the crust will eventually loosen and shed on its own. It is important not to pick at this crust, as premature removal can disrupt the healing process and increase the risk of spreading the infection or leaving a temporary mark.
Expected Treatment Timeline and Signs of Concern
Treatment for impetigo, whether with a topical antibiotic ointment or an oral antibiotic, is effective and shortens the duration of the illness. Patients begin to see noticeable improvement within 48 to 72 hours of starting the medication. This early sign of improvement confirms the bacteria are being killed and the infection is resolving.
The entire course of the lesions, from initial sore to complete healing, is generally completed within seven to ten days with proper treatment. It is crucial to finish the entire course of antibiotics, even if the sores appear healed, to ensure all the bacteria are eradicated and to prevent the development of antibiotic resistance.
True worsening of the infection that requires immediate medical attention is rare but distinct from the normal crusting process. Signs of a complication include the infection spreading rapidly outside the localized area after two days of treatment, or if the sores become deeply painful. Systemic symptoms like a persistent fever, sudden streaks of redness extending from the sore, or the development of large, pus-filled ulcers known as ecthyma also warrant an urgent medical review.