Prevalence, risk factors, and clinical characteristics of bacterial skin infections. A comprehensive review

Nº de DOI: 10.34896/RSI.2025.62.63.001

AUTHORS

1. Edwin Andrés Toapanta Chiluisa. General Practitioner and Master’s Degree in Health Institution Management. Attached to Health District 02D03 Chimbo San Miguel. Graduate of the Central University of Ecuador. (Latacunga-Ecuador). https://orcid.org/0000-0002-0426-5570 ciru gener udl
2. Doménica Cristina Serrano Salinas. General Practitioner. Attached to Homero Castanier Crespo Hospital. Graduate of the Catholic University of Cuenca. (Cuenca-Ecuador). https://orcid.org/0000-0001-5313-9127
3. Mariela Viviana Torres Salguero. General Practitioner. Attached to Riobamba General Hospital. Graduate of the National University of Chimborazo. (Riobamba -Ecuador). https://orcid.org/0009-0004-3816-0373
4. Rodrigo Fernando Cabrera Jadán. General Practitioner and Master’s Degree in Occupational Health and Safety. Attached to Labovida Quito Headquarters. Graduate of the Technical University of Loja. (Quito-Ecuador). https://orcid.org/0009-0004-4641-6797
5. Cristie Vanessa Salazar Holguin. Nursing Assistant. Graduate of the Bolivarian Technical Institute. (Daule-Ecuador). https://orcid.org/0009-0005-6341-0714

ABSTRACT

This review aims to synthesize current evidence on these aspects, providing a detailed overview of their global impact and identifying gaps that warrant further investigation.

KEY WORDS

Bacterial skin infections, epidemiology, global prevalence, antimicrobial resistance.

RESUMEN

Esta revisión tiene como objetivo sintetizar la evidencia actual sobre estos aspectos, proporcionando una visión detallada de su impacto global e identificando lagunas que requieren investigaciones adicionales.

PALABRAS CLAVE

Infecciones bacterianas de la piel, epidemiología, prevalencia global, resistencia a los antimicrobianos.

INTRODUCTION

Bacterial skin infections represent a significant and pervasive public health challenge, affecting individuals across all age groups and socioeconomic backgrounds worldwide. These infections, which include conditions such as impetigo, cellulitis, folliculitis, and abscesses, are characterized by their diverse clinical presentations and varying degrees of severity, often leading to considerable morbidity if not properly diagnosed and managed. Epidemiologically, the prevalence of bacterial skin infections exhibits notable regional and demographic disparities, with higher rates observed in low- and middle-income countries, among children, and in populations with limited access to adequate hygiene and healthcare resources. Over recent decades, trends have indicated fluctuations in incidence rates, partly driven by evolving environmental factors, socioeconomic changes, and the alarming rise of antibiotic-resistant strains that complicate treatment protocols and increase the risk of recurrent infections. Several risk factors have been identified, including underlying medical conditions such as diabetes mellitus and immunosuppression, poor hygiene practices, environmental exposures, and the pervasive challenge of antibiotic resistance, which collectively contribute to susceptibility and complicate management strategies. Clinically, bacterial skin infections manifest through a spectrum of signs—from erythema, swelling, and pain to pustules and ulcerations—necessitating accurate differentiation from other dermatological conditions through a combination of clinical examination and laboratory diagnostic tools, including bacterial cultures and molecular assays. Understanding the complex interplay of epidemiological patterns, risk factors, and clinical features is essential for developing effective prevention and treatment strategies, underscoring the importance of comprehensive research into the prevalence, determinants, and diagnostic approaches for bacterial skin infections.

OBJECTIVE

Synthesize current evidence on these issues, providing a detailed overview of their global impact and identifying gaps that warrant further investigation.

METHODOLOGY

This narrative review was conducted with the aim of synthesizing current evidence on the global and regional epidemiology, risk factors, clinical characteristics, diagnostic approaches, and antimicrobial resistance patterns of bacterial skin infections. A comprehensive literature search was carried out in major electronic databases, including PubMed, Scopus, Web of Science, and Google Scholar, covering publications from 1990 to 2024.

The search strategy used combinations of the following terms and their synonyms: “bacterial skin infections,” “skin and soft tissue infections,” “SSTIs,” “cellulitis,” “impetigo,” “MRSA,” “antibiotic resistance,” “epidemiology,” “incidence,” “prevalence,” “risk factors,” “diagnosis,” “clinical features,” and “management.” Reference lists of key articles and relevant reviews were also manually screened to identify additional studies.

Inclusion criteria comprised:

1. Peer-reviewed original research articles, epidemiological studies, clinical trials, and systematic reviews.
2. Studies reporting data on incidence, prevalence, risk factors, clinical presentation, diagnostic methods, or antimicrobial resistance related to bacterial skin infections.
3. Global or regional data, including low, middle, and high SDI settings.

Exclusion criteria included:

1. Case reports and small case series with limited generalizability.
2. Articles not focused primarily on bacterial skin infections (e.g., exclusively fungal, viral, or parasitic skin diseases).
3. Non-English language publications when full translation was not available.

Data from eligible studies were extracted and synthesized narratively according to major thematic domains: (1) global and regional epidemiology, (2) demographic and socioeconomic determinants, (3) underlying medical and immunocompromising conditions, (4) hygiene and environmental factors, (5) antibiotic resistance and recurrence, and (6) clinical features and diagnostic tools. Due to heterogeneity in study designs, populations, and outcome measures, no meta-analysis was performed. Instead, a qualitative synthesis was prioritized to integrate findings, identify knowledge gaps, and highlight implications for clinical practice and public health.

RESULTS

Epidemiology and Prevalence of Bacterial Skin Infections:

What is the global and regional prevalence of bacterial skin infections?

Globally, the prevalence of bacterial skin infections is marked by significant variation across regions, age groups, and socio-demographic contexts, underscoring the complexity of their epidemiology and the interlinked nature of contributing factors. The overall incidence of bacterial skin diseases has exhibited a notable increase, rising from 8,988.74 per 100,000 individuals in 1990 to 10,823.88 per 100,000 in 2021, emphasizing a persistent upward trend in the global burden of these conditions¹. At the regional level, Sub-Saharan Africa experiences the highest prevalence, while the Caribbean and Southeast Asia report the lowest incidence rates, reflecting stark contrasts likely influenced by differences in healthcare infrastructure, climate, and socioeconomic status¹. The burden is particularly concentrated among infants, adolescents, and young adults, with approximately 50 million cases in populations aged 0 to 35 years in 2021, and a notably high incidence persisting in people under 30 years old¹. This age-specific burden is further complicated by an increase in incidence among the elderly, especially those aged 85 and above, suggesting that both the youngest and oldest populations are at heightened risk¹. These epidemiological patterns are further shaped by socio-demographic indices, low SDI regions bear the highest incidence rates, often exacerbated by limited access to healthcare and preventive resources, while high SDI areas see rises in disease burden primarily due to epidemiological transitions rather than absolute incidence¹. The significant regional and demographic disparities in prevalence highlight the need for tailored public health interventions, improved surveillance, and better access to care in high-burden areas, as well as sustained research efforts to comprehensively evaluate and address the global impact of bacterial skin diseases¹.

What trends have been observed over time in the incidence of bacterial skin infections?

Over the past several decades, a discernible upward trend has been observed in the incidence of bacterial skin and soft tissue infections (SSTIs), highlighting a growing public health concern that transcends individual patient care and extends into broader healthcare and societal domains². Notably, data indicate that the annualized incidence rate of SSTIs increased by 7.38% from 1990 to 2019, and this rise is mirrored by the persistently increasing disease burden associated with these infections². The interconnection between rising incidence and the evolving landscape of antimicrobial resistance further complicates this issue, the prevalence of multi-drug-resistant bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA), has surged significantly over time, with MRSA accounting for up to 36.4% of S. aureus isolates in recent studies^2,3. This escalation in resistance not only exacerbates therapeutic challenges but also fuels the cycle of recurrent infections, prolonged morbidity, and increased healthcare costs, thereby amplifying the overall disease burden. Compounding these clinical challenges, the growing prevalence of resistant strains necessitates robust surveillance, improved infection control strategies, and the development of novel antimicrobial therapies to mitigate the impact of bacterial skin infections on public health³.

Risk Factors Associated with Bacterial Skin Infections:

What underlying medical conditions increase susceptibility to bacterial skin infections?

A range of underlying medical conditions can significantly heighten an individual’s vulnerability to bacterial skin infections, primarily through their impact on immune system function and skin integrity. Immunocompromised states, whether resulting from chronic diseases or the medications used to treat them, are well-established contributors to increased infection risk⁴. For instance, individuals living with HIV/AIDS experience a marked reduction in immune competence, rendering them less able to mount effective defenses against common bacterial pathogens that affect the skin⁵. Similarly, diabetes not only impairs immune responses but also disrupts normal skin barrier function and blood circulation, collectively creating an environment conducive to bacterial colonization and infection⁵. Cancer patients, particularly those undergoing chemotherapy or radiotherapy, often face immunosuppression that further exacerbates their susceptibility to skin infections by diminishing leukocyte counts and disrupting protective barriers⁶. Additionally, certain medications, including corticosteroids and immunosuppressants, can directly suppress immune activity or alter inflammatory responses, compounding the risk for those with pre-existing health conditions⁴. These interconnected factors underscore the necessity for targeted clinical vigilance and proactive management strategies in populations with such underlying medical conditions, aimed at timely identification and intervention to prevent the escalation of bacterial skin infections.

How do hygiene practices and environmental exposures contribute to risk?

Hygiene practices and environmental exposures are intricately linked to the risk of infectious diseases and broader health outcomes, given their dual influence on both the prevention of harmful microbial transmission and the maintenance of beneficial microbial diversity. While effective hygiene routines—such as regular cleaning, handwashing, and proper laundering—are essential for minimizing contamination and reducing the spread of infections within households and communities, these interventions must be carefully balanced to avoid excessive elimination of microbial exposure that is critical for immune system development and microbiome health⁶. The challenge lies in implementing hygiene measures that effectively target pathogens while still allowing for contact with beneficial environmental microbes, as lack of exposure to diverse microbial communities from natural, human, and animal sources has been associated with increased incidence of autoimmune disorders and other non-communicable diseases⁶. Moreover, exposures to environmental hazards, such as air and water pollution or toxic industrial by-products, can exacerbate health risks and complicate the picture by simultaneously increasing vulnerability to infection and disrupting microbial ecosystems⁶. Thus, the interconnections between hygiene practices and environmental exposures underscore the need for evidence-based interventions that promote infection control, environmental sustainability, and immune resilience. Prioritizing such balanced approaches is crucial for mitigating risk in diverse populations and ensuring long-term public health.

What is the role of antibiotic resistance in the development and recurrence of infections?

Antibiotic resistance plays a pivotal role in both the development and recurrence of infections by enabling bacteria to evade the effects of otherwise effective treatments⁷. When bacteria acquire resistance, they continue to grow and multiply despite the presence of antibiotics, resulting in persistent and sometimes more severe infections⁷. This survival advantage not only allows resistant strains to flourish within an individual but also increases the likelihood that these bacteria will be transmitted to others, contributing to the broader public health threat of recurring infections⁷. The recurrence is often driven by the fact that resistant bacteria survive initial antibiotic therapy, remain in the host, and can subsequently cause new episodes of infection that are much harder to treat⁸. Furthermore, the transfer of resistant traits among bacteria—via mechanisms such as plasmid exchange—facilitates the spread of resistance within microbial communities, compounding the challenge of managing recurrent infections⁸. These interconnected dynamics underscore the urgent need for interventions aimed at curbing the misuse and overuse of antibiotics, as well as the implementation of robust infection control measures to prevent the proliferation and recurrence of antibiotic-resistant infections.

Clinical Characteristics and Diagnosis of Bacterial Skin Infections

What are the common clinical presentations of major bacterial skin infections?

Major bacterial skin infections typically present with a constellation of signs and symptoms that serve as key diagnostic indicators for clinicians. Most commonly, patients exhibit erythema, pain, warmth, and swelling at the site of infection, with the degree of dysfunction correlating to the severity of the condition^9,10. These hallmark features are often accompanied by purulent discharge and regional lymphadenopathy, which further aid in distinguishing bacterial etiologies from other types of dermatoses⁹. Notably, cellulitis—a prevalent and clinically significant form of bacterial skin infection—affects the deeper dermal and subcutaneous layers, demonstrating the potential for these infections to range from superficial to deep tissue involvement¹⁰. The diversity of presentations, from localized lesions to more diffuse or systemic manifestations, underscores the importance of recognizing both classic and atypical clinical patterns in order to facilitate timely intervention and prevent complications¹⁰. Given the broad spectrum of presentations, ongoing clinical vigilance, comprehensive skin examinations, and patient education are essential interventions for effective management and prevention of major bacterial skin infections.

How are bacterial skin infections differentiated from other dermatological conditions?

The differentiation of bacterial skin infections from other dermatological conditions relies on a multifaceted assessment incorporating clinical appearance, symptomatic presentation, anatomical location, and the specific skin layers involved¹¹. While cutaneous manifestations can overlap with non-bacterial etiologies, certain features such as erythema, warmth, purulent exudate, and localized pain are significant indicators suggestive of bacterial origin, which tend to distinguish them from viral, fungal, or inflammatory skin disorders¹¹. Despite some variability in presentation—rooted in the type of bacterial agent and individual patient factors—core symptoms like swelling, tenderness, and occasionally systemic signs such as fever are relatively consistent across bacterial skin infections, providing clinicians with crucial diagnostic clues¹¹. Recognizing these patterns is particularly essential in global contexts where the burden of bacterial skin diseases is high, as early and accurate identification enables timely intervention, limits transmission, and informs appropriate treatment strategies, underscoring the need for heightened clinical vigilance and standardized diagnostic protocols¹¹.

What diagnostic tools and laboratory methods are most effective for confirming bacterial skin infections?

To accurately confirm bacterial skin infections, a multifaceted diagnostic approach integrating both clinical and laboratory methods is essential. Initial patient evaluation typically begins with a physical examination and symptom review, which helps clinicians determine the likelihood of infection and guides subsequent testing¹². Laboratory analysis of skin samples is then pivotal for detecting the specific pathogens responsible, this process commonly involves collecting specimens through swabbing, scraping, or biopsy of the affected area^12,13. The skin culture and sensitivity test is a cornerstone in this process, as it not only identifies bacterial or fungal organisms but also evaluates their resistance or sensitivity to various antibiotics, thereby ensuring that treatment is both targeted and effective¹³. In addition to cultures, Gram staining of exudate or tissue samples provides rapid preliminary identification of bacteria, enabling early therapeutic decisions while awaiting definitive culture results¹⁴. For deep or ambiguous infections, obtaining cultures and Gram stains from deep tissue at the time of operation offers the most definitive bacteriologic diagnosis, as superficial wound cultures may not reliably reflect the causative organism¹⁴. Furthermore, blood cultures and, when indicated, direct needle aspiration of inflamed areas can yield diagnostic information, particularly in cases where systemic involvement or deeper infection is suspected¹⁴. Given the risk of sampling errors and false negatives, especially with biopsies, integrating multiple diagnostic modalities is often necessary to ensure accuracy and prevent misdiagnosis¹⁴. Thus, an effective diagnostic pathway for bacterial skin infections should combine clinical assessment with a range of laboratory techniques, emphasizing the importance of comprehensive evaluation to guide appropriate treatment interventions and improve patient outcomes.

DISCUSSION

The findings of this comprehensive review underscore the escalating global burden of bacterial skin infections, highlighting significant regional disparities that are influenced by socioeconomic, environmental, and healthcare infrastructure factors. The observed increase in prevalence over the past three decades, particularly among vulnerable populations such as infants, young adults, and the elderly, emphasizes the need for targeted public health interventions. The disproportionately higher rates in low SDI regions suggest that limited access to preventive measures, diagnostic tools, and effective treatments continue to perpetuate these infections, thereby exacerbating health inequities. Moreover, the rise of antimicrobial resistance, especially with the proliferation of MRSA strains, presents a formidable challenge to traditional treatment modalities, complicating clinical management and prolonging recovery times. The clinical features delineated—such as erythema, pain, and purulent discharge—are essential for initial diagnosis, yet the overlap with other dermatoses calls for reliable laboratory confirmation through cultures and molecular diagnostics to prevent misdiagnosis and ensure appropriate antimicrobial use. Despite these insights, the review also highlights gaps in current knowledge, including the need for standardized diagnostic protocols across diverse healthcare settings and more robust epidemiological data from underrepresented regions like Southeast Asia and the Caribbean. Additionally, future research should focus on the development of novel antimicrobial agents and vaccines, alongside strategies to curb antimicrobial resistance. Limitations such as variability in reporting standards and potential publication bias should be acknowledged, as they may influence the accuracy of prevalence estimates and risk factor associations. Ultimately, addressing bacterial skin infections on a global scale demands a multifaceted approach that combines improved diagnostic accuracy, antimicrobial stewardship, health education, and socioeconomic development to reduce incidence and mitigate adverse outcomes.

CONCLUSIONS

1. The global epidemiological landscape of bacterial skin infections reveals a persistent and escalating burden, with incidence rates increasing steadily over the past three decades. This trend is not uniformly distributed, as Sub-Saharan Africa and other low SDI regions face disproportionately higher prevalence, reflecting gaps in healthcare infrastructure, socioeconomic inequities, and environmental exposures that amplify transmission and limit access to timely care.
2. Demographic patterns demonstrate a bimodal vulnerability, with infants, young adults, and elderly populations exhibiting the highest rates of infection, likely due to biological susceptibility and differences in immune competence. Furthermore, the emergence and dissemination of antibiotic-resistant strains, particularly methicillin-resistant Staphylococcus aureus (MRSA), have compounded clinical and public health challenges, increasing recurrence rates, treatment failures, and healthcare costs.
3. Clinically, the presentation of bacterial skin infections often overlaps with other dermatological conditions, underscoring the importance of accurate and standardized diagnostic strategies—including cultures, Gram staining, and molecular testing—to ensure appropriate therapeutic interventions. Despite advances in clinical microbiology and surveillance, regional disparities in diagnostic capacity and reporting standards limit the accuracy of prevalence estimates and hinder the implementation of targeted control strategies.

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