Skin/Soft Tissue and Bone/Joint Infections

What is folliculitis?

Inflammation of the hair follicle caused by physical injury, chemical irritation, ingrown hair, or infection

What is the most common etiology of folliculitis?

Staph aureus

What are 3 other causes of folliculitis?

1. Community associated MRSA

2. Candida spp.

3. Pseudomonas aeruginosa

Describe the treatment for folliculitis

1. Warm, moist heat to promote drainage

2. Good hygiene practices

3. If severe, topical antimicrobials (mupirocin)

When are anti-infectives needed for folliculitis?

Not needed unless extensive lesion or fever is present

What is a furuncle?

A boil, a painful, pus-filled bump under the skin caused by infected, inflamed hair follicles. Can progress to form abscesses if left untreated

How do furuncles compare to folliculitis?

They are deeper and more severe. Occur when folliculitis spreads to the subcutaneous tissue around the follicle

Furuncles describe...

lesions that occur in individual hair follicles

What is the most common etiology of furuncles?

Staph aureus

What are 3 other possible causes of furuncles?

1. Community associated MRSA

2. Candida spp.

3. Pseudomonas aeruginosa

Describe the treatment for furuncles

1. Warm, moist heat to promote drainage

2. Good hygiene practices

3. If large, incision and drainage

4. If severe, topical antimicrobials (mupirocin)

What are anti-infectives needed for furuncles?

Not needed unless extensive lesion or fever is present

What are carbuncles?

Cluster of boils. Painful, pus-filled bumps that form a connected area of infection under the skin. People who have a carbuncle often feel unwell in general and may experience a fever and chills

How do carbuncles compare to furuncles?

Carbuncles (cluster) cause a deeper and more severe infection and may leave a scar

What is the most common etiology of carbuncles?

Staph aureus

What are 3 other possible causes of carbuncles?

1. Community associated MRSA

2. Candida spp.

3. Pseudomonas aeruginosa

Describe the treatment for carbuncles

1. Warm, moist heat to promote drainage

2. Good hygiene practices

3. If large, incision and drainage

4. If severe, topical antimicrobials (mupirocin)

What are anti-infectives needed for carbuncles?

Not needed unless extensive lesion or fever is present

Pharmacologic treatment for folliculitis, furuncles, and carbuncles may be used if the patient exhibits...

systemic symptoms such as fever or has associated cellulitis

What drugs can be used for folliculitis, furuncles, and carbuncles when caMRSA is suspected?

1. trimethoprim-sulfamethoxazole

2. clindamycin

3. doxycycline

4. minocycline

What is erysipelas?

Infection limited to the superficial layer of the skin (epidermis) and the cutaneous lymphatics

What are some physical characteristics of erysipelas?

Intensely red and burning lesion with clearly demarcated, raised margins

What is the most common etiology of erysipelas?

Group A strep

What 2 drugs are most commonly used to treat erysipelas?

Penicillin or Clindamycin (has good anti-toxins)

What is impetigo?

Superficial skin infection that occurs in children and individuals with poor hygiene during hot and humid weather months. Hot and humid environments facilitate microbial colonization and overgrowth

What are some physical characteristics of impetigo?

Microorganisms invade through breaks in the skin and cause blisters that rupture and form a golden-yellow crust over the lesions

What is the most common etiology of impetigo?

Staph aureus and group A strep

What non-pharm supportive treatment options are there for impetigo?

Soaking lesions with soap and water and then using skin emollients to dry areas

What drugs are used to treat severe impetigo?

Cephalexin and dicloxacillin

What is lymphangitis?

Inflammation of the lymphatic channels that occurs when a local skin infection spreads into the lymphatics. An uncontrolled infection can progress rapidly to cause serious complications

What are some physical characteristics of lymphangitits?

Erythematous streaks that extend from the original infection site to the lymph nodes.

What is the most common etiology of lymphangitis?

Group A strep, sometimes staph aureus

What is used to treat lymphangitis?

Parenteral penicillin or clindamycin should be started within 48-72 hours

What is cellulitis?

An acute, infectious process that affects the epidermis and dermis, potentially spreading to the superficial fascia. Mark spread with a blue pen

What are some physical signs/symptoms of cellulitis?

Painful and tender with rapidly spreading signs of redness, edema, and warmth

How is cellulitis different from erysipelas?

The cellulitis lesion has poorly defined margins and is not raised

What is the most common etiology of cellulitis?

Group A strep, Staph aureus, sometimes other gram (+), gram (-), or anaerobic pathogens

What are 4 non-pharm treatments for cellulitis?

1. Elevating and immobilizing the limb to decrease swelling

2. Placement of sterile saline dressings on open lesions

3. Surgical debridement for severe infection

4. Drainage of abscesses (if present)

What pharmacologic treatment is often used for cellulitis?

Anti-staph penicillin, MRSA treatment, BL/BLI

What is necrotizing fasciitis? When does this occur?

A rare, rapidly progressive, and life-threatening infection of the subcutaneous tissue and fascia. Occurs after a trauma causes a minor abrasion or deep penetrating wound that introduces bacteria into the fascia, which then releases toxins

What is the difference between type 1 and type 2 necrotizing fasciitis?

Type 1 develops after surgery or deep penetrating wounds in the bowel, decubitus ulcer

Type 2 occurs after minor trauma from an abrasion or insect bite

What is the most common etiology for type 1 necrotizing fasciitis?

Often polymicrobial containing anaerobes, strep, enterics

What is the most common etiology for type 2 necrotizing fasciitis?

Group A strep, MRSA

What treatment is used for necrotizing fasciitis?

1. Surgical intervention

2. BL/BLI or a carbapenem in combo with clindamycin and a parenteral MRSA-active antibiotic like vancomycin, linezolid, or daptomycin (clinda added to decrease bacterial toxin production to minimize further damage)

A diabetic foot infection is from...

chronic foot ulcers

What is the most common etiology for diabetic foot infections and pressure sores?

Staph aureus, strep, enterics, anaerobes, pseudomonas

How are bite wounds treated?

1. Irrigation and debridement as soon as possible

2. Most do not require antibiotic therapy in absence of infection

3. Changing environment adds on risk for different types of bugs, need more broad antibiotic without culture like a BL/BLI

What is osteomyelitis?

Infection of the bone

What are the 3 categories of osteomyelitis?

1. Hematogenous

2. Contiguous

3. Secondary to vascular insufficiency

What/who does hematogenous osteomyelitis affect?

Often occurs in children and affects the long bones

What/who does contiguous osteomyelitis affect?

Mostly adults, arises from infections of adjacent tissues or organs, and most commonly encountered after surgery

What/who does vascular insufficiency osteomyelitis affect?

Occurs mostly in older adults or those with diabetes. It affects the lower limbs and can be difficult to treat due to decreased blood flow to the area

What is the common etiology for the 3 kinds of osteomyelitis?

Hematogenous = staph aureus

Contiguous & Vascular insuf. = staph aureus, strep, enterics, anaerobes

What is the treatment for osteomyelitis?

1. Deep culture and surgical intervention (if possible) should be performed prior to treatment with systemic antibiotics

2. Multiple antibiotic options exist