Impetigo is a common bacterial skin infection, usually caused by Staphylococcus aureus or Streptococcus pyogenes, that primarily affects the outermost layer of the skin. Because the infection is generally superficial, the vast majority of cases do not result in permanent, true scarring. Instead, the residual marks that appear after the infection clears are typically temporary changes in skin color, which fade over time.
Differentiating True Scars from Skin Discoloration
A true scar represents permanent damage and alteration to the skin’s structure, occurring when trauma or inflammation penetrates deep into the dermis layer. This damage results in a loss or overgrowth of tissue, creating a depressed or atrophic scar, or a raised scar. Impetigo, in its common non-bullous and bullous forms, remains confined to the epidermis, the skin’s surface layer, which is why it heals without changing the skin’s texture.
The most frequent residual marks are forms of temporary discoloration known as Post-Inflammatory Hyperpigmentation (PIH) and Post-Inflammatory Hypopigmentation (PIPO). PIH manifests as flat, darkened patches of skin, ranging from tan to brown or even black, and occurs when the skin produces excess melanin in response to the inflammation caused by the infection. PIPO, conversely, results in lighter or depigmented patches where the inflammation has temporarily reduced melanin production.
These pigment changes are not structural damage. Since the underlying tissue structure remains intact, these marks fade as skin cells naturally turn over and the excess pigment is eliminated. PIH is more noticeable and persistent in individuals with naturally darker skin tones due to higher melanin production.
Factors Influencing Scarring Potential
While true scarring is uncommon, its potential relates directly to the depth and severity of the initial infection and how the area is treated. A deeper variant of impetigo called ecthyma penetrates through the epidermis and into the dermis, making it a high-risk condition for permanent scarring. Ecthyma causes deep, open sores that crust over and can leave behind scars after healing.
Physical trauma to the lesions significantly increases the risk of deeper infection and persistent marks. Scratching, picking, or scrubbing at the crusts or blisters can push bacteria and inflammation deeper into the skin layers. This disruption prolongs the inflammatory phase, leading to a greater and more long-lasting pigment response, which exacerbates PIH.
Delayed or incomplete antibiotic treatment raises the likelihood of complications and deeper tissue involvement, particularly the progression to ecthyma. The presence of pre-existing skin conditions, such as eczema or active wounds, compromises the skin barrier, allowing the infection to establish itself more aggressively. Lesions located on areas with thinner skin or constant friction may be more prone to prolonged inflammation and visible residual marks.
Managing and Fading Residual Marks
The temporary discoloration left by impetigo will gradually fade on its own, but this process can take several months, sometimes extending up to a year or more. Strict, daily sun protection is essential to prevent the darkening of PIH. Ultraviolet (UV) exposure stimulates melanin production, which darkens existing hyperpigmentation and prolongs the fading process.
A broad-spectrum sunscreen with an SPF of 30 or higher, applied daily, helps prevent UV-induced darkening. Certain over-the-counter topical ingredients can accelerate the fading process by regulating pigment production or encouraging cell turnover. Ingredients such as niacinamide, Vitamin C (ascorbic acid), or mild retinoids encourage the skin to shed pigmented cells more quickly.
For more persistent marks, dermatologists may recommend prescription-strength options or in-office procedures. These treatments include chemical peels, microdermabrasion, or specific laser therapies designed to break down excess melanin. True, depressed scars resulting from ecthyma require different and often more invasive treatments, such as dermal fillers or subcision, than temporary color changes.