What are Bacterial Skin and Soft tissue Infections?
Bacterial skin and soft tissue infections (SSTIs) are infections involving the skin, the tissues underneath it, and sometimes the muscles and deeper layers. These infections can range from mild to severe and can be caused by various types of bacteria.
Common Types of Bacterial Skin and Soft Tissue Infections
Some of the common types of bacterial skin and soft tissue infections include:
- Cellulitis: A common infection that affects the deeper layers of the skin and the subcutaneous tissues. It is usually caused by Streptococcus or Staphylococcus bacteria, including MRSA (Methicillin-resistant Staphylococcus aureus). Symptoms include redness, swelling, warmth, and pain in the affected area.
- Impetigo: A highly contagious superficial infection, often seen in children. It is primarily caused by Streptococcus pyogenes or Staphylococcus aureus and appears as red sores or blisters that can rupture, ooze, and form a honey-colored crust.
- Erysipelas: A superficial form of cellulitis that affects the upper dermis. It is typically caused by Streptococcus pyogenes and is characterized by raised, red, and sharply demarcated areas of skin, often on the face or legs.
- Folliculitis: This involves infection of the hair follicles. It is typically caused by Staphylococcus aureus and other bacteria and appears as small, red bumps or pustules at the base of hair follicles.
- Abscesses: A collection of pus that has built up within the tissue of the body. It is often caused by Staphylococcus aureus, particularly MRSA and appears as a swollen, red, and painful lump under the skin.
- Necrotizing Fasciitis: A rapidly spreading infection that destroys the muscles, fat, and skin tissue. It is often caused by Streptococcus pyogenes, Staphylococcus aureus, or other bacteria. This condition requires urgent medical treatment due to its severity and rapid progression.
Risk factors for Bacterial Skin and Soft Tissue Infections
Some of the common risk factors for bacterial skin and soft tissue infections include:
- Compromised Immune System: Conditions like diabetes, HIV, or cancer can increase the risk.
- Skin Injuries: Cuts, abrasions, or insect bites can provide entry points for bacteria.
- Poor Circulation: Conditions like peripheral artery disease or chronic venous insufficiency can predispose individuals to SSTIs.
Diagnosis of Bacterial Skin and Soft tissue Infections
Diagnosis of bacterial skin and soft tissue infections may involve the following:
- A review of your medical history such as any recent trauma, surgery, insect bites, or underlying conditions (e.g., diabetes, immunosuppression).
- Physical examination to inspect the affected area for signs of infection, such as redness (erythema), swelling (edema), warmth, tenderness, and the presence of abscesses or ulcers.
- Laboratory tests, such as wound culture to help identify the causative organism and its antibiotic susceptibility and blood tests to look for elevated white blood cells which indicates infection.
- Skin or tissue biopsy to examine the affected area under a microscope and to culture the tissue.
Treatment for Bacterial Skin and Soft tissue Infections
Treatment of bacterial skin and soft tissue infections depends on the severity of the infection, the causative organism, and the patient's overall health. Treatment may typically involve:
Antibiotic Therapy:
- Topical Antibiotics:
- Used for mild, superficial infections like impetigo or minor folliculitis.
- Common topical antibiotics include mupirocin or fusidic acid.
- Oral Antibiotics:
- Prescribed for more extensive but non-severe infections, such as uncomplicated cellulitis or abscesses.
- Common oral antibiotics include cephalexin, clindamycin, doxycycline, and amoxicillin-clavulanate.
- For suspected or confirmed MRSA (Methicillin-resistant Staphylococcus aureus), antibiotics like trimethoprim-sulfamethoxazole, doxycycline, or clindamycin are used.
- Intravenous (IV) Antibiotics:
- Required for severe infections or when oral antibiotics are ineffective or inappropriate (e.g., in hospitalized patients).
- Common IV antibiotics include vancomycin, ceftriaxone, piperacillin-tazobactam, and linezolid.
Surgical Intervention:
- Incision and Drainage:
- Necessary for abscesses or larger boils where pus needs to be evacuated.
- Often combined with antibiotic therapy for optimal treatment.
- Debridement:
- Removal of dead or infected tissue, especially in severe infections like necrotizing fasciitis.
- This is a critical step to prevent the spread of the infection and promote healing.
Supportive Care:
Pain management, wound care, and addressing underlying conditions such as diabetes or peripheral vascular disease are also important in the management of SSTIs.