Bacterial infections Flashcards
(30 cards)
Classification of bacterial skin infections
Pyodermas
Non pyodermas
Soft tissue infections
Pyoderma definition
Purulent bacterial infection of the skin
Causative agents of pyoderma
Group A beta hemolytic streptococci
Staphylococcus aureus
Corynebacteria
Kytococcus
Pseudomonas
Pyoderma classification
Primary
Secondary
Primary pyodermas
Superficial:
a. Follicular:
1. Superficial folliculitis
2. Follicular impetigo
b. Non follicular:
1. Impetigo
Deep:
a. Follicular:
1. Furuncle
2. Carbuncle
3. Sycosis barbae
b. Non follicular:
1. Ecthyma
2. Erysipelas
3. Cellulitis
4. Paronychia
5. Necrotizing fascitis
Secondary pyodermas
Infected eczema
Infected ulcers
Impetigo types
- Non bullous impetigo/impetigo contagiosa
- Bullous impetigo
Non bullous impetigo:
definition, causative organism, clinical features, complications
Bacterial infection of epidermis
Group A streptococcus, Staphylococcus aureus
Golden brown honey coloured crests in perioral and perinasal areas
Age group: children
Complications:
Post streptococcal glomerulonephritis
Bullous impetigo:
causative organism, lesion, clinical features
Staphylococcus aureus
Flaccid bullae with varnish crust, Hypopyon sign positive
Location: Trunk
Ecthyma:
Causative agent, Lesion
Group A Streptococci
Chocolate brown, thick adherent crust -> purulent irregular ulcer
Erysipelas:
Causative agent, Lesion, Margins, level, location
Group A streptococci
Lesion : Erythematous indurated well defined plaque
Margins : Well defined, raised margins
Level: Upper half of dermis + lymphatics
Location : Lower extremities
Cellulitis:
Causative agent, Lesion, Margins, Level, Location
Causative agent:
Group A Streptococci
Staphylococcus aureus
Lesion: Erythematous indurated tender plaque
Margins: Ill defined, diffuse margins
Location: Lower extremities
Sycosis barbae : Causative organism, clinical features
Erythematous follicular discreet papules or pustules -> coalesce -> Raised plaque studded with pustules -> fig like appearance
Milan sign
Cellulitis of face does not involve ear unlike erysipelas
Foliculitis, Furuncle, Carbuncle definitions
Infection of hair follicles
Infection of hair follicles + perifollicular area
Infection of multiple hair follicles + contiguous areas
Treatment of folliculitis, furuncle and carbuncle
Topical antibiotics
Topical antibiotics
Systemic antibiotics
Surgical treatment: Incision and drainage, Surgical debridement of affected areas
Staphylococcus scalded skin syndrome definition
Acute skin exfoliation caused by toxin producing strains of staphylococcus aureus
SSSS:
pathogenesis
focus of infection (conjunctivitis/otitis media) -> Epidermolytic exotoxin production -> Hematogenous spread -> Reaches target (target protein : Desmosomes, target antigen : Desmoglein -1) -> Acantholysis
SSSS: Clinical features
History of conjunctivitis or otitis media
Fever
Periorificial erythema, Crusting
Skin exfoliation
Sheet like epidermal peeling
True nickolsky sign
How is SSSS differentiated from TEN
Hemorrhagic crusts in mucosa are seen in TEN
SSSS does not affect lips
Acute paronychia:
Definition, predisposing factors, clinical features
Nail fold infection
Thumb suckling
Nail fold erythema, edema, tenderness, pus collection
Botryomycosis:
definition, causative organisms, Lesions
Chronic, suppurative, granulomatous disease in response to a bacterial pathogen
Staphylococcus aureus, proteus, klebsiella, e coli
Nodules + ulcers
Erysipeloid:
causative organism, risk factors, lesions
Erysiplethorix rhusiopathiae
Meat/fish handlers
Purplish erythema, painful edema
Cutaneous corynebacterial infections
Erythrasma
Trichomycosis axillaris
Pitted keratolysis
