Transcript Bacterial Infection

‫به نام خدا‬
‫دکترعلیرضا واعظ شوشتری‬
‫متخصص پوست‬
Bacterial infections of Skin
Normal flora of skin
• Classification:
1. Resident flora: grow on skin & relatively
stable in no. and composition at particular sites
2. Transient flora: lie on skin surface without
attachment, unable to multiply & disappear
within short time
Normal Skin Flora
• Major bacterial groups
– Coryneforms
- Staphylococci (Gram +ve cocci, aerobs)
S. epidermidis, S. hominis, S.hemolyticus, S. saprophyticus
• Minor bacterial groups
– Acinetobacter (25%)
– Micrococci
• Fungal group
– Pityriasporum
Bacterial infection of the skin
(Pyoderma)
Classification of pyodermas
1. Primary
 Impetigo
 Ecthyma
 Folliculitis
– Superficial
– Deep
* Furuncle
* Carbuncle
* Sycosis Barbae
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2.
Cellulitis/ Erysipelas
Pyonychia
SSSS
TSS
Secondary
Secondary infection of preexisting dermatoses
eg. Atopic dermatitis, Scabies
Impetigo (contagious superficial infection)
Non-bullous
Bullous
1. Cause
- Streptococcal (Group A)
- Staph. aureus (Phage Groups II)
2. Pre-school and young school age
3. Very thin walled vesicle on an erythematus base
4. Transient
5. Yellowish-brain crusts (thick)
Staph. aureus
All ages
Bullae of 1-2cm
Persist for 2-3 day
Thin, flat,
brownish crust
Contd…
6. Irregular peripheral extension without
healing
Central healing with
peripheral extension
7. Regional adenitis
8. Constitutional symptoms present
9. Face (around the nose, mouth & limbs)
10. Palms & sole spared
Rare
Absent
occur anywhere
May involved
Predisposing factors
– Malnutrition
– Diabetes
– Immuno-compromise status
Complications
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Streptococcal infection
PSGN (strep M-type 49)
Scarlet fever
Urticaria
Erythema mutiforme
Ecthyma
• Streptococcal & staph
• Common in children
• Small bullae or pustules on erythematous base
• Formation of adherent dry crusts
• Beneath which ulcer present
• Indurated base
• Heals with scar and pigmentation
• Buttocks, thighs and legs, commonly affected
Folliculitis
• Superficial folliculitis
• Infection of hair follicles
• Commonly caused by staph. aureus
• Children
• Scalp & limb
• Rarely painful
• Heals in a week
Furuncle (Boil)
• Acute
• Staph. aureus
• Small, follicular noduler -- Pustule--necrotic-discharge pus
• Painful
• Constitutional symptoms
• Heals with scar
• Age: Adult
• Site: Neck, Wrist, Waist, Buttocks, Face
Complication
• Cavernous Sinus thrombosis, (upper lip & check)
• Septicemia (malnutrition)
Carbuncle
• Extensive infection of a group of contagious follicles
• Staph. aureus
• Middle or old age
• Predisposing factors
– Diabetes
– Malnutrition
– Severe generalized dermatoses
– During prolonged steroid therapy
• Painful, hard lump
• Suppuration begins after 5-7 days
• Pus discharge from multiple follicular orificies
• Necrosis of intervening skin
• Large deep ulcer
• Constitutional symptoms
Sycosis barbae
• Beard region
• Pustules surrounded by erythema
• Males
• After puberty
• After trauma
• Upper lip and chin
• Staph. aureus
Cellulitis
• Acute/sub-acute/chronic
• Inflammation of loose connective tissue
• Streptococcal (Group A)
• Erythematous, edematous, swelling
• Pain/tenderness
• Constitutional upset
Pyonychia
• Acute
• Erythematous swelling of proximal and lateral
nail fold
• Painful
Staphylococcal scalded skin syndrom
(Ritter’s Disease)
• Exotoxin of staph (Phage Group II)
• Acantholysis
• Occult staph. upper respiratory tract infection or
purulent conjunctivitis
• Infants and children
• Tender red skin
Staphylococcal scalded skin synotrane
(Ritter’s Disease)
• Denuded skin
• Heals 7 - 14 day
• Don’t grow staph. from blister fluid
• Complication 2%
– Cellulitis
– Pneumonia
• Prognosis : good / 3% death
Principles of therapy of pyoderma
• Good personal hygiene
• Management of predisposing factors
– Local
• Attend to traumas, Pressure, Sweating, Bites
• Treat pre-existing dermatosis
• Investigate carrier sites: Nose, Axilla, Perineum
Systemic
• Treatment of disease like DM
• Nutritional deficiency
• Immunodeficiency
Principles of therapy of pyoderma
• Local therapy
– Cleaning with soap-water and weak KMN04
solution
– Removal of crusts with KMN04 soluation
– Application of antibacterial cream
• Systemic therapy
– Antibiotics
Recurrent staphylococcal infection
• Persistent nasal carriage
• Abnormal neutrophitic chumotaxis
• Deficient intracellular killing
• Immunodeficient status
• D.M.
T/t of staph. carriage elimination
• Nasal & perineal care
• Rifampicin 600 mg/d 7-10 days
• Clindamycin 150 mg/d 3 months
• Topical mupirocin
S.aureus produces skin infection
I. Direct infection of skin and adjuscent tissues
a.
b.
c.
d.
e.
f.
Impetigo
Ecthyma
Folliculitis
Furunculosis
Carbuncle
Sycosis
II.Cutaneous disease due to effect of bacterial toxin
a.
b.
Staphylococcal scalded skin syndrome
Toxic shock syndrome
ß-hemolytic streptococcus produces
skin infection
I. Direct infection of skin or subcutaneous
a.
b.
c.
d.
e.
f.
g.
Impetigo (non bullous)
Ecthyma
Erysipelas
Cellulitis
Vulvovaginitis
Blistering distal dactylitis
Necrotizing fascitis
II. Secondary infection
Eczema infection
III. Tissue damage from circulating toxin
Scarlet fever
IV. Skin lesion attributed to allergic hypersensitivity
to streptococcal antigens
E.Nodosum
Vasculitis
V. Skin disease provocated or influenced by
streptococcal infection (mechanism uncertain)
Guttate psoriasis
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