Bacterial Skin and Soft Tissue Infections
Abscess Forming Infections
Types of Infection
Folliculitis

Inflammation and
infections of hair
follicles
Treatment
1. Cloxacillin
2. Surgery
a. Carbuncle

Etiological Agents
Staphylococcus aureus
Structure Involved
 Localized infection
in the
o Hair follicles
o Axillae
o Scalp
o Ear canal
 Leads to Otitis
Externa
Clinical Features
1. Small
2. Erythematous
a. Papules
b. Pustules
3. Course of folliculitis
a. Develop into Furuncle
i. Deeper inflammatory nodules
b. Furuncle can then extend deeper into
subcutaneous fat called Carbuncle
i. Bigger
ii. Deeper
iii. Due to multiple draining sinuses
iv. Occurs at
1. Nape of neck
2. Thigh
Spreading Infections
Impertigo
1. The most common superficial epidermal infection
2. Due to
a. Poor hygiene
b. Hot and humid climate
3. Common in children
Types of Infection
Etiological Agents
Non bullous Impertigo
 Streptococcus pyogenes
 More common
 Nephrotogenic strain of
 Begins with small
Strep pyogenes type M49
vesicles
o Causing nono Ruptures causing
suppurative sequale
superficial spread
o Acute
Treatment
glomerulonephritis
1. Penicilin
Bullous Impertigo
 Staphylococcus aureus
phage type 71
Treatment
o Produces exfoliatin
1. Cloxacillin
Cellulitis

A diffuse
inflammation and
infection of
superficial skin layers
Erysipelas
Deeper form of cellulitis
Perdisposing factors
o
Diabetes mellitus
o
Venous stasis
o
Alcohol abuse
Treatment

Cloxacillin



Penicillin
Structure Involved
 Epidermis
Clinical Features
1. Serous exudates in the vesicles
2. Ruptures to produce GOLDEN-CRUSTED
erosions

Epidermis
1. Bullae or vesicles containing turbid fluid (serum)
2. Dangerous in infant, requires systemic
antibiotics
1. Localized area of
a. Mildly painful edema
b. Warmth
c. Swollen
2. Severe systemic infection
a. Fever
b. Rigors
1. Usually occurs at the face
2. Involvement of lymphatic drainage gives rise to
clearly demarcated area of
a. Erythema
b. Induration


Streptococcus pyogenes
Staphylococcus aureus
(polymicrobial)

Epidermis


Streptococcus pyogenes
Staphylococcus aureus
(polymicrobial)


Underlying dermis
Lymphatic
channels
Necrotizing infections
Types of Infection
Gas
Gangrene/Clostridial
Myonecrosis


Etiological Agents
Clostridium perfringens
Clostridium septicum
Structure Involved
 Muscles
 Soft tissues
Predisposing factors
(60-70%)
o Motor vehicle
accident
o Penetrating injury
o Crush injury
Treatment
 Surgical debridement
o Amputation might be
required
 Penicillin

Necrotizing Fascitis
Streptococcus
pyogenes
 Acute and highly toxic
o Flesh-eating bugs
Predisposing Factors
 Polymicrobial
1. Post surgery
o Aerobic/facultative
2. Post trauma
anaerobe
3. Strep pyogenes skin
 Staph aureus
infection
 Strep spp.
4. Diabetes mellitus
 Enterococcus
 Enterobacteriacea
Treatment
o Anaerobic
1. Surgical exploration
a. Removal of death tissues
 Bacteroides spp.
b. Determine extend of
 Clostridium spp.
tissue damage
2. Combination of
antibiotics


Widespread
infection of the
fascia
Clinical Features
Pathogenesis
1. Production of alpha toxin  tissue death
2. Production of gas in the necrotic lesions
3. Cell death leads to destruction of blood supply to the
affected tissues
4. Favors anaerobic condition, which in return organism will
further replicate
Features
1. Initial presentation appears 4-6 hours after trauma
2. Local tenderness
3. Skin appears
a. Stretch
b. Shining
c. Later blackens
4. Foul smelling discharge
5. Crepitus
6. Systemic symptoms
a. Sweating
b. Tachycardia
1. Devascularization of
a. Skin
b. Muscle
c. NOT INCLUDING BONE
2. Skin necrosis
3. Bullae formation
4. Surrounding tissue edema and inflammation
5. Gangrenous
6. Crepitus
7. Pts appears toxic with soft tissue pain
Systemic Bacterial Infection with Cutaneous Involvement
Types of Infection
Staphylococcus
Scalded Skin
Syndrome (SSSS)
Etiological Agents
 Staphylococcus aureus
o Exfoliatin strain
Structure Involved
1. Cutaneous
manifestation
a. Epidermis
Staphylococcus aureus
o TSST-I toxin (exotoxin)
1. Involved multiple
organs
2. Cutaneous
manifestation
a. Epidermis and
dermis
1. Also known as
a. Infant
i. Ritter’s diseases
(not to be
confused with
Ritter’s syndromes)
b. Children/adult
i. Toxic epidermal
necrolysis
2. May occur
sporadically or in
outbreak
Treatment
1. Fluid replacement
therapy
2. Cloxacillin
Toxic Shock
Syndrome
Treatment
1. Fluid replacement
therapy
2. Cloxacillin

1.
2.
3.
4.
Clinical Features
Toxin causes loss of overlying skins
Toxiemia
Fever
Death
1. Happens in women using tampon
2. Can also occur in non-genital site in men
3. Erythematous rash
4. Skin dequamation of
a. Palms
b. Soles
Micellaneous Skin Infections
Types of Infection
Etiological Agents
Erysipelothrix
rhusiopatheiae
Erysipeloid
 Suspect in handlers of
o Fishes
o Meats

Erythrasma

Corynibacterium
minutissimum
Cat Scratch Disease
Treatment
1. To shorten the course of the disease
a. Tetracyclin
b. Erythromycin

Bartonella Henselae
Cutaneous Anthrax
 Due to direct inoculations from
o Infected animals
o Contaminated animal products
Treatment
1. Penicillin

Bacillus anthracis
Animal’s Bite Infections
Treatment


Pasteurella multocida
Often polymicrobial
o Aerobes

Staph spp.

Strep spp.
o Anaerobes

Bacteroides

Anaerobic cocci
1. Thorough cleaning
2. Debridement of all damaged tissues
3. Combination antibiotics
4. Penicillin for Pasteurella multocida
Clinical Features
1. Tender
2. Blue-red discoloration of the skin
3. Well demarcated
1. Often assymptomatic
2. Slowly enlarging area of dry skin which either
a. Pink
b. Brownish
3. Erythema spreads in moist and skin folds such as
a. Axillae
b. Groin
c. Between toes
1. Following cat scratch
2. Nodule formation at scratched area
3. Regional lymphadenopathy
a. Resolves in 1-6 months
4. Self limited
1.
2.
3.
4.
Inflammed lesion with surrounding edema
PAINLESS
Variable skin lesions
If not treated, may progress into
a. Septiceamia
b. Death
1. Skin loss leads to sf tissue damages
2. Exposure to animal saliva and foreign particles lead to
secondary skin infection
3. Cellulitis
4. Lymphagitis
5. Localized abscess