Skin and Soft tissue infections

Short notes on skin and soft tissue infections

1. Skin and Soft Tissue Infections Sanjaya Gihan Weerasinghe

2. Infections in, Skin Subcutaneous tissue Fasciae Muscles

3. Erysipelas Strep. Infections of dermis Well demarcated, painful, erythematous indurated plaques, Blisters & ulceration  Abrupt fever with chills Face, legs common in very young, old, debilitated patients lymphoedematous erysipelas and Cellulitis overlap often Treatment: Penicillin IV/IM

4. Impetigo A contagious superficial infection of the skin Staphylococci or β- haemolytic streptococci common in children usually involves the skin of the face, often around the mouth and nose. spread by direct contact Minor abrasions and other skin lesions predispose to infections Prevention is by good personal hygiene , particularly hand washing with soap.

5. It has two forms: Non- bullous Streptococcus pyogenes "honey-crust" lesions Bullous Staphylococcus aureus rupture of the bullae "varnish-like" crust

6. Treatment Usually self-limiting Avoid precipitating factor (e.g., exfoliation ) Localized topical fusidic acid tds. (for MRSA) mild and localized – Topical antibiotic e.g.; topical mupirocin Extensive disease oral flucloxacillin, Erythromycin

7. Other close contacts should be examined children should avoid school for 1week after starting therapy. resistant to treatment or recurrent take nasal swabs and check other family members. Eradication of nasal carriage Nasal mupirocin

8. Folliculitis Infections of the superficial part of the hair follicle itchy or tender papules and pustules. Staphylococcus aureus

9. Small pustules often pierced by a hair Legs, face – ( sycosis barbae) commoner in humid climates and when occlusive clothes are worn. Extensive, itchy folliculitis in HIV infection.

10. Treatment topical antiseptics topical sodium fusidate mupirocin containing ointment oral antibiotics flucloxacillin or erythromycin If chronic – Detect and treat carrier state

11. Boils (furuncles) Staph. Infections of the deeper part of hair follicle most common on the face, neck, armpit, buttocks, and thighs On central face danger of cavernous sinus thrombosis Tender, red, cone shaped swelling heal with scarring Recurrences may occur Exclude carrier state Treatment: Antibiotics If large – need incision

12. CARBUNCLE Deep staph. Infection of several adjacent hair follicle  cluster of boils that form a connected area of infection neck, back, thighs In diabetics & debilitated Treatment Antibiotics, Surgical incision

13. Ecthyma By both streptococci and staphylococci Ulcer forms under a crusted surface of the infection Heals with scarring

14. Poor hygiene and malnutrition are predisposing factors Minor injuries and other skin conditions determine the site Treatment- Improved hygiene and nutrition Antibiotics ( phenoxymethylpenicillin and flucloxacillin)

15. Cellulitis Infection of  normal skin flora or exogenous bacteria ( S . aureus and ß- haemolytic streptococci)   Deep skin or subcutaneous layer Hx of Trauma and Ulceration Organisms enter through breach in skin Infection can spread to blood stream Bacteremia /septicemia. lower leg , hand ,nose ,periorbital

16. Clinical features Acute localised pain Oedema lymphangitis &lymphadenitis Hot painful erythema streaking, progressing proximally from the affected area, tracking along lymphatics +/- blister Fever, Malaise, Leucocytosis

17. Predisposing factors Diabetes Alcoholism Malignancy Drug abuse venous stasis lymphoedema

18. Investigations Swabs taken from relevant sites (from leading edge or aspirating blisters) Gram stain and Blood cultures Serological- antistreptolysin O titre (ASOT) antiDNAse B titre (ADB)

19. Management Elevate limb. Treat underlying Cause Antibiotics Phenoxymethylpenicillin erythromycin flucloxacillin (all 500 mg qds ) Vancomycin Linezolid Clindamycin Widespread IV antibiotics (3–5 days) ,2 weeks (oral) Recurrent low dose antibiotic prophylaxis ( phenoxymethylpenicillin ) MRSA Cellulitis

20. Complications-Local Blisters Skin necrosis Thrombophlebetics Lymphadenitis Abscesses

21. Bacteremia Septicemia Osteomyelitis Meningitis Complications-Systemic

22. Skin abscess Subcutaneous localized collection of pus surrounded by granulation tissue Hx of penetrating injury infection of haematoma

23. S. aureus is the common infecting organism Poor hygiene is predisposing Rx- incision and drainage Features : Cellulitis present Swollen Soft center feels like fluid underneath Painful Tender Cellulitis Abscess

24. Necrotizing fasciitis Surgical emergency Polymicrobial Infection of the fascia Type 1- E.coli, Pseudomonas, Proteus, Bacteroides, Clostridium Type 2- Streptococcus May proceed rapidly to underlying muscle. Diagnosis is often delayed Primarily a clinical diagnosis Rapid progression to septic shock Mortality 30-50%

25. Clinical Features Severe pain at the site of initial infection Tissue necrosis . spreading erythema pain soft tissue crepitus (infection tracks rapidly along the tissue planes) Fever ,Tachycardia

26. Diagnose on signs and symptoms. Imaging- air in the tissues.

27. Clinical findings in necrotising fasciitis Early findings Pain Cellulitis Pyrexia Tachycardia Swelling Skin anesthesia Late findings Severe pain Skin discoloration (purple or black) Blistering Hemorrhagic bullae Crepitus Discharge of “dishwater” fluid Severe sepsis or systemic inflammatory response syndrome Multi-organ failure

28. Treat aggressively and promptly antibiotics T ype 1- Broad-spectrum combination ( amoxicillin , imipenem , levofloxacin ) Type 2 benzylpenicillin and clindamycin

29. urgent surgical exploration Extensive debridement or amputation (if necessary) Necrotizing fasciitis after debridement

30. Staphylococcal scalded skin syndrome exfoliate or epidermolytic toxin. rapidly spreading tender erythema Dermonecrosis Outer layer of the epidermis peel off Blistering Ritter's Disease of the Newborn - most severe form of SSSS

31. Affects infants, immunosuppressed , renal disease, Malignancy Mortality – higher in adult Diagnosis Clinical Culture Frozen section examination of skin – shows split Treatment: IV antibiotics & nursing care or Self limiting.

32. Hidradenitis suppurativa Infection in Apocrine sweat glands Common in Axillae and groin and in females Multiple tender swellings Enlarging and discharging pus Recurrence worse in obese individuals Rx- weight loss oral retinoids (Vitamin A) Zinc gluconate

33. Erythrasma Chronic skin infection of Corynebacterium Macular wrinkled, slightly scaly pink ,brown or macerated white areas armpits ,groin or between toe webs Coral pink under Wood’s light prevalent among diabetics, the obese, and in warm climates Rx – Topical fusidic acid ,Miconazole

34. Pyomyositis S. aureus & Streptococcus infection of the skeletal muscles  pus-filled abscess most common in tropical areas- “  myositis tropicans ” can affect any skeletal muscle most often infects the large muscle groups e.g.-quadriceps or gluteal muscles

35. Fever, Sepsis, Localized inflammation Muscle pain Predisposing factors- Immunodeficiency, IVDAs, Trauma and malnutrition Complications- Abscess, sepsis Rx- Drain surgically and antibiotics

36. Gangrene Clinical situation where extensive tissue necrosis is complicated by bacterial infection Dry gangrene Wet gangrene Gas gangrene Predisposing factors Serious injuries Ischemia due to atherosclerosis and PVD Diabetes

37. Dry Gangrene The result of ischaemic coagulative necrosis. Black, dry, sharply demarcated Secondary bacterial infection is insignificant E.g. Gangrene of extremities in thrombo -embolic occlusion of vessels

38. Wet Gangrene Tissue necrosis is complicated by severe infection. Swollen, reddish-black foul smelling tissue. Extensive liquefaction of dead tissue occurs due to invasion of organisms & acute inflammation. No clear demarcation between dead and viable tissue. Occurs in extremities and internal organs E.g. Diabetic gangrene of foot Gangrene of bowel

39. Gas Gangrene ( Clostridial myonecrosis ) Clostridium perfringens Extensive tissue destruction gas production by fermentative action of bacteria. Swollen reddish-black foul smelling tissue with crepitus.

40. Treatment usually surgical debridement amputation (if necessary) Antibiotics alone are not effective

41. Thank you!