Eczema, also known as atopic dermatitis, creates a vulnerability in the skin that significantly raises the risk of bacterial infection, particularly from Staphylococcus aureus (Staph). While eczema does not directly cause the bacteria, it creates the conditions for S. aureus to thrive and invade. S. aureus is commonly found on the skin of healthy people, but approximately 80% of individuals with atopic dermatitis have colonization, compared to only 10% to 20% of the general population. This common skin resident can quickly transition into an active infection when the protective barrier is compromised.
The Direct Link: Eczema and Staph Colonization
The connection between eczema and Staph infection stems from defects in the skin’s natural defenses. The skin barrier in atopic dermatitis is structurally flawed, often due to genetic variations affecting proteins like filaggrin. A filaggrin deficiency leads to increased water loss and dry, cracked skin. This compromised barrier is easily penetrated by microbes and environmental irritants.
The skin’s immune response is also dysregulated, resulting in a reduced production of natural antimicrobial peptides (AMPs). These AMPs act as the body’s localized antibiotics. Their lower concentration allows S. aureus to colonize the skin surface extensively, meaning the bacteria are present in high numbers without causing an active infection. The bacteria exploit the weakened barrier, forming a dense population.
Once S. aureus has colonized the skin, it is poised to cause an active infection. The constant itching associated with eczema leads to scratching, which creates micro-abrasions and open wounds. These breaks serve as direct entry points, allowing the high load of bacteria to move into deeper tissue. The bacteria also produce virulence factors that further damage the skin barrier and trigger inflammation, worsening the eczema itself.
Recognizing a Secondary Skin Infection
When colonized S. aureus transitions to an active infection, it is known as a secondary infection or impetiginization. The first sign is often a sudden, unexplained worsening of eczema, especially if maintenance treatments fail. Local symptoms include the development of yellow or honey-colored crusts, caused by the drying of serum and pus. The infected areas may also ooze fluid, and pus-filled blisters (pustules) can appear within the rash.
Unlike a typical eczema flare, the skin may feel intensely painful, tender, and warm to the touch, indicating a localized inflammatory response. Increased redness or darkening of the skin color can also signal a deeper issue. If the infection spreads beyond the skin, systemic symptoms require immediate medical attention.
Systemic symptoms include:
- A fever, chills, and a general feeling of malaise.
- Swollen lymph nodes, particularly near the infected area (neck, armpits, or groin).
Recognizing these signs early is important to prevent the infection from becoming more severe or widespread.
Treatment and Management of Infected Eczema
Treatment for infected eczema must address both the underlying skin condition and the bacterial invasion, requiring medical consultation. For localized infections, a physician typically prescribes a topical antibiotic cream applied directly to the patches. If the infection is widespread, severe, or unresponsive to topical treatment, oral antibiotics are necessary. Doctors may swab the area first to identify the bacteria and determine the most effective antibiotic, especially if resistance is suspected.
It is important to complete the entire course of antibiotics as prescribed to ensure the infection is fully eradicated. Adjunctive therapies are often recommended to reduce the overall S. aureus burden on the skin surface. Diluted bleach baths, prepared under a physician’s guidance, can act as a topical antiseptic for recurrent infections. Maintenance treatment of eczema, including moisturizing and topical anti-inflammatory medications, must continue alongside antibiotics to repair the damaged skin barrier.
Preventing Future Infections
Preventing future bacterial infections relies on consistently maintaining a healthy and intact skin barrier. Adhering to a daily eczema management regimen reduces the risk of colonization and subsequent infection. This includes regular, liberal application of emollients and moisturizers to seal in hydration and reinforce the skin’s physical barrier function.
Strategies aimed at minimizing skin trauma are also crucial, as broken skin provides the entry point for bacteria. Keeping fingernails short and smooth helps reduce the damage caused by scratching, especially during sleep. For recurrent infections, a doctor may recommend a short decolonization routine using topical antiseptic washes. Good hygiene habits, such as frequent handwashing and regularly washing bedding and towels, help minimize bacterial load.