Skin Infections: Types, Symptoms & Treatment

What Are Skin Infections?

Skin infections occur when pathogenic organisms – bacteria, viruses, fungi, or parasites – breach the skin's natural protective barrier and multiply within the tissue. These infections can affect the epidermis (outer skin layer), dermis (middle layer), subcutaneous tissue (fat layer), or even spread to deeper structures like muscle and bone in severe cases.

The skin serves as the body's first line of defense against infectious agents. This remarkable organ weighs approximately 8 pounds in adults and covers about 22 square feet of surface area. It maintains a slightly acidic pH and hosts a diverse microbiome of beneficial bacteria that help prevent pathogenic organisms from establishing infections. When this barrier becomes compromised – through cuts, abrasions, insect bites, surgical incisions, or underlying skin conditions – infectious agents can gain entry and cause disease.

Skin infections represent a significant global health burden, accounting for 7-10% of all dermatological consultations in primary care settings. The annual incidence of cellulitis alone is approximately 200 cases per 100,000 population in developed countries, with rates being considerably higher in tropical regions and among immunocompromised individuals. The economic impact includes direct medical costs, lost productivity, and in severe cases, hospitalization and surgical intervention.

Understanding the different types of skin infections is crucial because treatment approaches vary significantly depending on the causative organism. Antibiotics that effectively treat bacterial infections have no effect on fungal or viral infections, and vice versa. Misdiagnosis can lead to prolonged illness, development of complications, and unnecessary antibiotic exposure that contributes to antimicrobial resistance – one of the most pressing public health challenges of our time.

The Skin's Defense Mechanisms

The skin employs multiple layers of defense against infection. The stratum corneum, the outermost layer of dead cells, provides a physical barrier that is continuously renewed. Sebaceous glands produce oils with antimicrobial properties, while sweat glands secrete substances that maintain the skin's protective acid mantle. Langerhans cells in the epidermis act as immune sentinels, detecting and responding to foreign invaders.

When pathogens do breach these defenses, the immune system mounts a rapid inflammatory response. This produces the characteristic signs of infection: redness (rubor), heat (calor), swelling (tumor), and pain (dolor). While these symptoms can be uncomfortable, they represent the body's attempt to contain and eliminate the infection. Fever may develop if the infection is more extensive or enters the bloodstream.

What Are the Different Types of Skin Infections?

Skin infections are classified by the type of organism causing them: bacterial (cellulitis, impetigo, folliculitis), fungal (athlete's foot, ringworm, candidiasis), viral (herpes simplex, warts, shingles), and parasitic (scabies, lice). Each type has distinct characteristics, symptoms, and treatment requirements.

The classification of skin infections is fundamental to appropriate diagnosis and treatment. While many skin infections may appear similar superficially – presenting with redness, swelling, and discomfort – the underlying cause determines the treatment approach. A bacterial infection requires antibiotics, a fungal infection requires antifungals, and a viral infection may require antivirals or simply supportive care. Using the wrong treatment not only fails to resolve the infection but can allow it to worsen or spread.

Beyond the type of organism, skin infections are also classified by their depth and location within the skin structures. Superficial infections involve only the epidermis and may resolve with topical treatments alone. Deeper infections involving the dermis or subcutaneous tissue typically require systemic (oral or intravenous) therapy. The most severe infections, such as necrotizing fasciitis, involve deeper structures including fascia and muscle, and constitute surgical emergencies.

Bacterial Skin Infections

Bacterial skin infections are the most common type of skin infection worldwide. The primary causative organisms are Staphylococcus aureus (including methicillin-resistant strains, MRSA) and Streptococcus pyogenes (Group A Streptococcus). These bacteria are commonly found on normal skin but cause infection when they enter through breaks in the skin barrier.

Cellulitis is one of the most common bacterial skin infections, affecting approximately 14.5 million people annually in the United States alone. It presents as a spreading area of redness, warmth, swelling, and tenderness, most commonly on the lower legs. The borders are typically poorly defined and may expand rapidly. Fever and malaise often accompany more extensive cases. Without treatment, cellulitis can progress to bacteremia (bloodstream infection), sepsis, or necrotizing fasciitis.

Impetigo is a highly contagious superficial bacterial infection most common in children aged 2-5 years. It manifests as honey-colored crusted lesions, typically around the nose and mouth. Non-bullous impetigo (the more common form) begins as small red papules that rupture, leaving characteristic golden crusts. Bullous impetigo produces larger fluid-filled blisters that rupture and leave thin, varnish-like crusts.

Folliculitis is an infection of hair follicles that presents as small red bumps or pustules surrounding individual hairs. It can be caused by bacteria (especially Staphylococcus), fungi, or even yeast. "Hot tub folliculitis" is caused by Pseudomonas aeruginosa and occurs after exposure to contaminated water in pools, hot tubs, or water slides.

Furuncles (boils) and carbuncles represent deeper follicular infections. A furuncle is a painful, pus-filled nodule that develops from an infected hair follicle. A carbuncle is a coalescence of multiple furuncles with several drainage points and is often associated with systemic symptoms like fever and malaise.

Fungal Skin Infections

Fungal skin infections, collectively known as dermatomycoses or dermatophytoses, are caused by organisms that thrive in warm, moist environments. The most common causative organisms are dermatophytes (fungi that infect keratin-containing structures like skin, hair, and nails), yeasts (particularly Candida species), and molds.

Athlete's foot (tinea pedis) is the most prevalent fungal infection, affecting up to 70% of adults at some point in their lives. It thrives in the warm, moist environment between toes and in footwear. Symptoms include itching, scaling, cracking, and redness, typically in the toe web spaces. Some cases present with vesicles (small blisters) on the soles or sides of the feet.

Ringworm (tinea corporis) presents as circular, scaly patches with raised borders and central clearing, giving the characteristic "ring" appearance. Despite its name, ringworm has nothing to do with worms – it's purely a fungal infection. It spreads through direct contact with infected individuals, animals (especially cats and dogs), or contaminated objects like towels or clothing.

Jock itch (tinea cruris) affects the groin area, presenting as an itchy, red, ring-shaped rash in the skin folds of the groin and inner thighs. It's more common in men and athletes, and often coexists with athlete's foot (the same organism can spread from foot to groin via contaminated towels or hands).

Candidiasis is caused by Candida yeast species, most commonly Candida albicans. It typically affects moist areas like skin folds (under breasts, in the groin, between fingers), the corners of the mouth (angular cheilitis), and around nails (paronychia). It presents as red, raw-looking skin with satellite pustules at the edges. Candidiasis is particularly common in diabetics, the immunocompromised, and those taking broad-spectrum antibiotics.

Viral Skin Infections

Viral skin infections are caused by various virus families and often have characteristic appearances that aid diagnosis. Unlike bacterial and many fungal infections, viral skin infections often cannot be cured but may be managed with antiviral medications or resolve spontaneously as the immune system controls the infection.

Herpes simplex causes both cold sores (HSV-1, typically affecting the mouth) and genital herpes (HSV-2, typically affecting the genitals). Initial infection may cause fever, malaise, and painful clusters of small blisters that ulcerate and crust over 7-10 days. The virus remains dormant in nerve ganglia and can reactivate periodically, causing recurrent outbreaks. Triggers include stress, illness, sun exposure, and menstruation.

Shingles (herpes zoster) is caused by reactivation of the varicella-zoster virus (the same virus that causes chickenpox) from dormancy in nerve roots. It presents as a painful, blistering rash in a characteristic band-like (dermatomal) distribution on one side of the body. Pain often precedes the rash by several days. Complications include postherpetic neuralgia (persistent nerve pain) and, if affecting the eye, serious vision problems.

Warts are caused by human papillomaviruses (HPV) and present as rough, raised growths most commonly on hands (common warts), feet (plantar warts), or genitals. They spread through direct contact and can persist for months to years before the immune system clears them. While most warts are harmless, genital warts can be associated with increased risk of certain cancers.

Molluscum contagiosum is caused by a poxvirus and presents as small, dome-shaped, flesh-colored bumps with a central dimple (umbilication). It's common in children and spreads through direct skin contact or contaminated objects. In healthy individuals, the infection is self-limiting but may persist for months to years.

What Are the Symptoms of Skin Infections?

Common symptoms of skin infections include redness, swelling, warmth, pain or tenderness, itching, pus or discharge, and sometimes fever. Bacterial infections typically cause more acute symptoms with rapid progression, while fungal infections often develop gradually with prominent itching and scaling.

Recognizing the symptoms of skin infections is essential for early treatment and prevention of complications. While different types of infections have some unique characteristics, many share common features that reflect the body's inflammatory response to infection. Understanding these symptoms helps in determining the urgency of care and the likely type of infection involved.

The cardinal signs of infection – redness, heat, swelling, and pain – were first described by the Roman physician Celsus nearly 2,000 years ago and remain the cornerstone of clinical diagnosis today. These signs result from increased blood flow to the affected area, dilation of blood vessels, and the influx of immune cells working to combat the infection. The intensity of these symptoms often correlates with the severity of the infection, though some severe infections may paradoxically cause numbness rather than pain due to nerve damage.

General Symptoms of Skin Infection

Most skin infections, regardless of type, produce some combination of the following symptoms:

• Redness (erythema): Increased blood flow causes pink to deep red discoloration of the affected skin. In darker skin tones, redness may appear as darkening, grayish, or purplish discoloration.
• Swelling (edema): Fluid accumulation in tissues causes visible enlargement and a feeling of tightness or fullness in the affected area.
• Warmth: Increased blood flow and metabolic activity produce localized heat that can be felt by touching the skin.
• Pain or tenderness: Inflammation stimulates pain receptors, causing discomfort that may range from mild tenderness to severe throbbing pain.
• Pus or discharge: Collection of dead immune cells, bacteria, and tissue debris may drain from the infection site. Pus color can indicate the type of bacteria present.
• Fever: Systemic response to infection, indicating the infection may be spreading or more severe.

Symptoms by Infection Type

Bacterial infection symptoms tend to develop rapidly over hours to days. Cellulitis produces spreading redness with poorly defined borders, often accompanied by red streaking along lymphatic channels (lymphangitis) and tender, swollen lymph nodes (lymphadenopathy). Abscesses form tender, fluctuant swellings filled with pus that may require surgical drainage. Impetigo creates characteristic honey-colored crusts that ooze and spread to surrounding areas.

Fungal infection symptoms typically develop more gradually and are characterized by intense itching. Scaling and flaking of the skin are prominent features. Many fungal infections produce characteristic ring-shaped patches with raised, active borders and central clearing. Nail involvement (onychomycosis) causes thickening, discoloration, and crumbling of affected nails.

Viral infection symptoms often include clusters of small blisters (vesicles) that rupture and crust over. Herpes infections are typically preceded by tingling, burning, or itching sensations (prodromal symptoms) at the site where blisters will appear. Shingles produces severe pain that may precede the visible rash by days. Warts are usually painless unless located on pressure-bearing areas like the soles of the feet.

What Causes Skin Infections?

Skin infections are caused when pathogenic organisms enter through breaks in the skin barrier – cuts, scratches, insect bites, surgical wounds, or underlying skin conditions. Risk factors include diabetes, immunosuppression, poor circulation, and skin conditions like eczema that compromise the skin's protective function.

Understanding the causes of skin infections involves appreciating both the infectious agents that cause them and the host factors that allow infection to establish. The skin is remarkably resistant to infection under normal circumstances, hosting trillions of beneficial microorganisms that compete with pathogens for resources. Infection occurs when this balance is disrupted or when the skin's physical barrier is breached.

The organisms that cause skin infections are ubiquitous in our environment. Staphylococcus aureus, the most common cause of bacterial skin infections, colonizes the noses of approximately 30% of healthy adults without causing disease. Dermatophytes are found in soil, on animals, and on infected humans. Herpes simplex virus infects an estimated 67% of the global population under age 50. Despite this constant exposure, infection occurs relatively rarely because of the skin's effective defenses.

Entry Points for Infection

Any disruption of skin integrity provides a potential entry point for infection:

• Traumatic wounds: Cuts, abrasions, punctures, and burns all breach the skin barrier. Even minor injuries like paper cuts can allow entry of pathogenic organisms if conditions are favorable.
• Insect bites and stings: Beyond the direct break in the skin, scratching of itchy bites introduces bacteria from under the fingernails and creates additional micro-abrasions.
• Surgical incisions: Despite sterile technique, surgical site infections affect 2-5% of patients undergoing surgery, making them one of the most common healthcare-associated infections.
• Injection sites: Intravenous drug use is a significant risk factor for skin and soft tissue infections, often with unusual or resistant organisms.
• Underlying skin conditions: Eczema, psoriasis, and other inflammatory skin conditions compromise barrier function and increase infection risk. The intense itching associated with these conditions leads to scratching that further damages the skin.
• Skin folds and moisture: Areas where skin surfaces touch – under breasts, in the groin, between toes – create warm, moist environments ideal for bacterial and fungal growth.

Risk Factors for Skin Infections

Certain conditions and circumstances significantly increase the risk of developing skin infections:

Diabetes mellitus is one of the most significant risk factors for skin infections. High blood sugar impairs immune function, damages blood vessels reducing oxygen delivery to tissues, and causes nerve damage that may prevent recognition of injuries. Diabetics are 2-4 times more likely to develop skin infections and more likely to experience complications including hospitalization and amputation.

Immunosuppression from any cause increases susceptibility to skin infections. This includes HIV/AIDS, cancer treatments, organ transplant medications, and autoimmune disease treatments. Immunocompromised individuals may develop infections from organisms that rarely cause disease in healthy people and may have more severe courses of common infections.

Peripheral vascular disease reduces blood flow to the extremities, impairing delivery of immune cells and antibiotics to infected tissues and slowing wound healing. Combined with diabetes, peripheral vascular disease dramatically increases the risk of serious skin infections and non-healing wounds.

Obesity creates additional risk through increased skin folds, altered immune function, and association with diabetes. The lower legs are particularly vulnerable due to venous insufficiency and chronic edema.

Poor hygiene allows accumulation of pathogenic organisms on the skin surface. Infrequent handwashing, shared personal items, and inadequate wound care all increase infection risk.

When Should You See a Doctor for a Skin Infection?

Seek medical care for skin infections if you have fever, rapidly spreading redness, severe pain, pus drainage, red streaks from the wound, diabetes or a weakened immune system, or if symptoms don't improve after 2-3 days of home care. Seek emergency care immediately for high fever, confusion, rapid heartbeat, or signs of widespread infection.

Determining when a skin infection requires professional medical attention versus when it can be safely managed at home is an important decision. While many minor skin infections resolve with simple home care measures, others can progress rapidly to serious or life-threatening conditions if not treated promptly. Understanding these warning signs can be literally life-saving.

The decision to seek care depends on multiple factors including the appearance and behavior of the infection, associated symptoms, and individual risk factors. A small area of redness around a minor cut in a healthy young adult is very different from the same finding in an elderly diabetic with vascular disease. Context matters significantly in assessing the severity and urgency of skin infections.

Signs Requiring Urgent Medical Attention

Contact a healthcare provider promptly or visit an urgent care facility if you experience:

• Fever (temperature above 38°C/100.4°F): Fever indicates the infection may be spreading beyond the local area and warrants medical evaluation.
• Rapidly spreading redness: If redness is expanding over hours rather than days, the infection may be progressing rapidly. Mark the border with a pen to track expansion.
• Red streaks extending from the infection: These indicate lymphangitis – spread of infection along lymphatic channels – and require prompt antibiotic treatment.
• Significant swelling or enlargement of nearby lymph nodes: Tender, swollen lymph nodes (lymphadenopathy) indicate the immune system is fighting to contain spreading infection.
• Wound producing pus or foul-smelling drainage: While some drainage is normal, increasing amounts of pus or development of odor suggest worsening infection.
• Symptoms not improving after 2-3 days of home treatment: Infections that don't respond to appropriate home care may need prescription medications or drainage.

Emergency Warning Signs

Seek emergency medical care immediately for:

• High fever with chills and rigors
• Confusion or altered mental status
• Rapid heartbeat or low blood pressure
• Severe pain that seems out of proportion to visible findings
• Skin that appears purple, black, or necrotic
• Blisters filled with dark or bloody fluid
• Crackling sensation (crepitus) when pressing on the skin
• Rapidly worsening symptoms over hours

These symptoms may indicate necrotizing fasciitis ("flesh-eating bacteria"), sepsis, or other life-threatening conditions. Necrotizing soft tissue infections have mortality rates of 20-40% even with aggressive treatment, and outcomes are significantly better with earlier intervention. Time is critical – do not delay seeking care for these symptoms.

How Are Skin Infections Treated?

Treatment depends on the type and severity of infection. Bacterial infections require antibiotics – topical for mild cases, oral or IV for severe cases. Fungal infections need antifungal medications. Viral infections may require antivirals or supportive care. Abscesses often need surgical drainage in addition to antibiotics.

Effective treatment of skin infections requires identifying the causative organism and selecting appropriate antimicrobial therapy. The choice between topical and systemic treatment depends on infection severity, location, and extent. Additionally, some infections require surgical intervention for optimal outcomes. Understanding these treatment principles helps patients know what to expect and improves adherence to prescribed regimens.

A fundamental principle in treating skin infections is the importance of completing the full course of prescribed antimicrobial therapy. Even when symptoms improve rapidly – which they often do within 2-3 days of starting appropriate treatment – stopping early can allow resistant organisms to survive and potentially cause recurrent, more difficult-to-treat infections. This contributes to the growing global problem of antimicrobial resistance.

Treatment of Bacterial Skin Infections

Mild bacterial infections limited to superficial skin layers can often be treated with topical antibiotics. Mupirocin (Bactroban) is particularly effective against staphylococcal and streptococcal infections and is the treatment of choice for impetigo. Fusidic acid and retapamulin are alternative options. Topical treatment is applied 2-3 times daily for 7-10 days.

Moderate to severe bacterial infections require oral antibiotics. First-line agents for uncomplicated cellulitis include cephalexin, dicloxacillin, or clindamycin. For suspected MRSA infection (often presenting as abscesses or in patients with prior MRSA history), trimethoprim-sulfamethoxazole or doxycycline are preferred. Treatment duration is typically 5-14 days depending on response.

Severe infections requiring hospitalization are treated with intravenous antibiotics. Common regimens include vancomycin (for MRSA coverage) plus piperacillin-tazobactam or a carbapenem for broad coverage including gram-negative organisms. Duration depends on clinical response but is typically 7-14 days or longer for deep infections.

Abscesses require incision and drainage (I&D) regardless of antibiotic therapy. Antibiotics alone cannot penetrate well into the pus-filled cavity, and drainage is the definitive treatment. Small abscesses may be drained in an office setting; larger or deeper collections may require operating room drainage. After drainage, the wound is typically packed to allow continued drainage and healing from the inside out.

Treatment of Fungal Skin Infections

Topical antifungals are first-line treatment for most superficial fungal infections. Options include azoles (clotrimazole, miconazole, ketoconazole), allylamines (terbinafine, naftifine), and ciclopirox. Application is typically twice daily for 2-4 weeks, continuing for 1-2 weeks after symptoms resolve to prevent recurrence.

Oral antifungals are necessary for extensive skin involvement, hair or nail infection, or when topical treatment fails. Terbinafine and itraconazole are most commonly used. Nail fungal infections require prolonged treatment – typically 6 weeks for fingernails and 12 weeks for toenails. Liver function tests may be monitored during prolonged oral antifungal therapy.

Treatment of Viral Skin Infections

Herpes simplex infections are treated with antiviral medications that reduce viral replication. Acyclovir, valacyclovir, and famciclovir are all effective. Treatment is most beneficial when started within 72 hours of symptom onset. Suppressive therapy with daily antivirals may be prescribed for patients with frequent recurrences.

Shingles (herpes zoster) treatment is most effective when started within 72 hours of rash onset. The same antiviral medications used for herpes simplex are effective, though at higher doses. Pain management is important, and some patients may benefit from corticosteroids to reduce inflammation. Postherpetic neuralgia may require ongoing pain management with gabapentin, pregabalin, or tricyclic antidepressants.

Warts can be treated with various modalities including topical salicylic acid, cryotherapy (freezing with liquid nitrogen), cantharidin, imiquimod, or procedural treatments like electrosurgery or laser therapy. Many warts resolve spontaneously within 2 years, so the decision to treat depends on symptoms, location, and patient preference.

How Can You Treat Minor Skin Infections at Home?

Minor skin infections can be managed at home with proper wound cleaning using soap and water, application of antiseptic or antibiotic ointment, keeping the area covered with clean bandages, and monitoring for signs of worsening. Over-the-counter antifungal creams effectively treat most athlete's foot and ringworm infections.

Many mild skin infections can be successfully managed at home with appropriate wound care and over-the-counter products. Home treatment is appropriate for small areas of infection in otherwise healthy individuals without fever or systemic symptoms. Proper wound care not only helps resolve existing infections but also prevents secondary bacterial infection of viral or fungal conditions.

The cornerstone of home treatment is cleanliness. Regular gentle cleaning removes bacteria, debris, and exudate that can impede healing. Keeping wounds covered protects them from further contamination and prevents spread to other body areas or other people. Monitoring for signs of worsening allows for timely escalation to medical care if needed.

Basic Wound Care for Minor Infections

1. Wash your hands thoroughly with soap and water for at least 20 seconds before and after touching the infected area.
2. Clean the affected area gently with mild soap and warm water. Remove any debris or crusted material. Pat dry with a clean towel.
3. Apply antiseptic if available. Options include dilute chlorhexidine, povidone-iodine, or over-the-counter antibiotic ointments like bacitracin or neomycin.
4. Cover with a clean bandage to protect the area and prevent spread. Change bandages at least once daily or when wet/dirty.
5. Monitor for improvement. You should see gradual reduction in redness, swelling, and pain over 2-3 days.

Home Treatment for Specific Conditions

For minor bacterial infections: Over-the-counter antibiotic ointments containing bacitracin or neomycin can help prevent or treat minor skin infections. Apply a thin layer to clean skin 2-3 times daily. Triple antibiotic ointment (neomycin/bacitracin/polymyxin B) is widely available but carries a higher risk of allergic contact dermatitis.

For fungal infections: Over-the-counter antifungal creams containing clotrimazole, miconazole, or terbinafine are effective for most athlete's foot and ringworm infections. Apply twice daily for 2-4 weeks, continuing for at least one week after symptoms resolve. Keep affected areas clean and dry, and change socks daily.

For cold sores: Over-the-counter docosanol (Abreva) cream may shorten healing time if applied at the first sign of symptoms. Keep lesions clean and dry. Avoid touching them and wash hands frequently to prevent spread. Over-the-counter pain relievers can help with discomfort.

How Can You Prevent Skin Infections?

Prevent skin infections by keeping skin clean and dry, washing hands frequently, treating cuts and wounds promptly, not sharing personal items, wearing protective footwear in public areas, managing conditions like diabetes, and keeping skin moisturized to prevent cracks and breaks in the skin barrier.

Prevention is always preferable to treatment, and many skin infections can be avoided with simple hygiene measures and attention to skin care. Understanding how infections spread and what makes the skin vulnerable allows for targeted prevention strategies. For people with recurrent skin infections, working with a healthcare provider to identify and address underlying risk factors can break the cycle of repeated infections.

The skin is remarkably resilient and has evolved multiple mechanisms to prevent infection. Supporting these natural defenses through good hygiene, proper nutrition, and prompt attention to skin injuries allows the skin to do its job effectively. When underlying conditions compromise skin defenses, additional preventive measures become important.

General Prevention Strategies

• Maintain good hand hygiene: Wash hands frequently with soap and water, especially before eating, after using the bathroom, and after touching potentially contaminated surfaces. Use hand sanitizer when soap and water aren't available.
• Keep skin clean: Regular bathing removes pathogenic organisms from the skin surface. Pay attention to skin folds and moist areas where bacteria and fungi thrive.
• Keep skin dry: Dry thoroughly after bathing, especially between toes and in skin folds. Use absorbent powder in areas prone to moisture. Change wet or sweaty clothing promptly.
• Protect skin integrity: Treat minor cuts, scrapes, and insect bites promptly with cleaning and bandaging. Avoid scratching itchy skin, which can introduce bacteria.
• Don't share personal items: Razors, towels, washcloths, and other personal items can transmit infections. Use your own items and wash them regularly.
• Wear protective footwear: Use sandals or water shoes in public showers, pools, and locker rooms to prevent athlete's foot and plantar warts.

Prevention for High-Risk Individuals

People with diabetes, immune suppression, or other conditions that increase infection risk need additional preventive measures:

• Optimize blood sugar control: Well-controlled diabetes reduces infection risk and improves healing when infections do occur.
• Inspect skin daily: Check for cuts, cracks, redness, or other signs of early infection, especially on feet and in areas that may not be easily visible.
• Moisturize regularly: Dry, cracked skin is vulnerable to infection. Use fragrance-free moisturizers to maintain skin hydration and barrier function.
• Wear well-fitting shoes: Ill-fitting footwear causes friction, blisters, and pressure injuries that can become infected.
• Seek care promptly: Don't wait to see if minor injuries improve – have them evaluated early to prevent progression.
• Consider preventive antibiotics: Some people with recurrent cellulitis benefit from prophylactic antibiotics, though this should be discussed with a healthcare provider.

What Are the Complications of Skin Infections?

Complications of untreated or severe skin infections include abscess formation requiring drainage, cellulitis spreading to deeper tissues, bloodstream infection (sepsis), necrotizing fasciitis (tissue death), osteomyelitis (bone infection), and permanent scarring. Prompt treatment significantly reduces complication risk.

While most skin infections resolve without long-term consequences, untreated or severe infections can lead to serious complications. Understanding these potential outcomes emphasizes the importance of appropriate and timely treatment. Certain populations – particularly diabetics, the immunocompromised, and those with poor circulation – are at higher risk for complications and warrant closer monitoring.

The progression from localized skin infection to life-threatening systemic illness can be rapid, sometimes occurring within hours. This is particularly true for certain aggressive organisms like Group A Streptococcus and certain strains of MRSA. Early recognition and treatment of skin infections is the best way to prevent these serious outcomes.

Local Complications

Abscess formation occurs when the body walls off an area of infection, creating a collection of pus that antibiotics cannot penetrate effectively. Abscesses require drainage – either through spontaneous rupture or surgical incision – to resolve. Without drainage, they may continue to enlarge, cause significant tissue damage, or rupture into surrounding tissues.

Tissue destruction and scarring can result from severe or prolonged infections. Infection causes direct tissue damage through bacterial toxins and indirect damage through the inflammatory response. Deep infections may destroy hair follicles, sweat glands, and other skin structures, resulting in permanent scarring and altered skin function.

Chronic or recurrent infection affects some individuals, particularly those with underlying risk factors. Recurrent cellulitis is common in patients with lymphedema, chronic venous insufficiency, or previous episodes of cellulitis. Breaking this cycle often requires addressing underlying conditions and may involve prophylactic antibiotics.

Spreading and Systemic Complications

Bacteremia and sepsis occur when bacteria enter the bloodstream. This can cause systemic inflammatory response syndrome (SIRS), sepsis, and septic shock – conditions with significant mortality even with aggressive treatment. Warning signs include high fever, rapid heart rate, rapid breathing, confusion, and low blood pressure.

Necrotizing soft tissue infections (including necrotizing fasciitis) are surgical emergencies in which infection rapidly spreads along fascial planes, destroying tissue as it progresses. These infections have high mortality rates (20-40% or higher) and often require extensive surgical debridement in addition to antibiotics. Early symptoms may be subtle – severe pain out of proportion to visible findings is a classic warning sign.

Osteomyelitis (bone infection) can develop when skin infections spread to underlying bone, particularly in diabetic foot infections. Osteomyelitis is difficult to eradicate and may require prolonged antibiotics (6 weeks or longer) and sometimes surgical removal of infected bone.

Endocarditis (heart valve infection) can occur when bloodstream infection seeds heart valves, particularly in patients with pre-existing valve abnormalities or prosthetic valves. This serious complication requires prolonged intravenous antibiotics and may necessitate valve replacement surgery.