Bacterial infections of Skin

1. Bacterial infections of Skin

2. Learning objectives of bacterial infectionsof skin

3. Learning objectives of bacterial infections of skin

4. 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 3. Transient or temporary residents

5. Normal Skin Flora Major bacterial groups Coryneforms (Gram +ve, pleomorphic rods) Corynebacterium (Aerobic & lipophilic) Brevibacterium (Aerobic & non-lipophilic) Propinobacterium (Anaerobic)

6. - Staphylococci (Gram +ve cocci, aerobs) S. epidermidis, S. hominis, S.hemolyticus, S. saprophyticus Minor bacterial groups Acinetobacter (25%) Micrococci Fungal group Pityriasporum

7. Bacterial infection of the skin (Pyoderma) Classification of pyodermas Primary Impetigo Ecthyma Folliculitis Superficial Deep Folliculitis of leg Furuncle Carbuncle Sycosis Barbae

8. Cellulitis/ Erysipelas Pyonychia SSSS TSS 2. Secondary Secondary infection of preexisting dermatoses eg. Atopic dermatitis, Scabies

9. Impetigo (contagious superficial infection) Non-bullous Bullous 1. Cause - Streptococcal (Group A) Staph. aureus - Staph. aureus (Phage Groups II) 2. Pre-school and young school age All ages 3. Very thin walled vesicle on an erythematus base Bullae of 1-2cm 4. Transient Persist for 2-3 day 5. Yellowish-brain crusts (thick) Thin, flat, brownish crust

10. 6. Irregular peripheral extension without Central healing with healing peripheral extension 7. Regional adenitis Rare 8. Constitutional symptoms present Absent 9. Face (around the nose, mouth & limbs) occur anywhere 10. Palms & sole spared May involved 11.MM, very rare May involved

11. Malnutrition Diabetes Immuno-compromise status Complications Streptococcal infection PSGN (strep M-type 49) Scarlet fever Urticaria Erythema mutiforme

14. 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

16. Folliculitis Superficial folliculitis Infection of hair follicles Commonly caused by staph. aureus Children Scalp & limb Rarely painful Heals in a week

18. Folliculitis Deep folliculitis of leg Chronic Staph. aureus Hair follicles of leg Multiple Atrophic scar

19. Furuncle (Boil) Acute Staph. aureus Small, follicular noduler -- Pustule--necrotic--discharge pus Painful Constitutional symptoms

20. Heals with scar Age: Adult Site: Neck, Wrist, Waist, Buttocks, Face Complication Cavernous Sinus thrombosis, (upper lip & check) Septicemia (malnutrition)

22. 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

23. Painful, hard lump Suppuration begins after 5-7 days Pus discharge from multiple follicular orificies Necrosis of intervening skin Large deep ulcer Constitutional symptoms

25. Sycosis barbae Beard region Pustules surrounded by erythema Males After puberty After trauma Upper lip and chin Staph. aureus

27. Cellulitis Acute/sub-acute/chronic Inflammation of loose connective tissue Streptococcal (Group A) Erythematous, edematous, swelling Pain/tenderness Constitutional upset

29. Pyonychia Acute Erythematous swelling of proximal and lateral nail fold Painful

30. Staphylococcal scalded skin synotrane (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

31. 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 : Rule

33. 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

34. 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

35. Recurrent staphylococcal infection Persistent nasal carriage Abnormal neutrophitic chumotaxis Deficient intracellular killing Immunodeficient status D.M.

36. T/t of staph. carriage elimination Nasal & perineal care Rifampicin 600 mg/d 7-10 days Clindamycin 150 mg/d 3 months Topical mupirocin Replacement of microflora with a less pathogenic stains of S.aurus (strain 502)

37. S.aureus produces skin infection I. Direct infection of skin and adjuscent tissues a. Impetigo b. Ecthyma c. Folliculitis d. Furunculosis e. Carbuncle f. Sycosis II. Cutaneous disease due to effect of bacterial toxin a. Staphylococcal scalded skin syndrome b. Toxic shock syndrome

38. ß-hemolytic streptococcus produces skin infection I. Direct infection of skin or subcutaneous a. Impetigo (non bullous) b. Ecthyma c. Erysipelas d. Cellulitis e. Vulvovaginitis f. Blistering distal dactylitis g. Necrotizing fascitis II. Secondary infection Eczema infection

39. 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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