Dermatology: Bacterial Infections and Viral Infections Overview

1. Dr Spandana P Hegde Senior Resident Dept of Dermatology BACTERIAL AND VIRAL INFECTIONS

2. BACTERIAL INFECTIONS • Introduction • Classification • Primary pyodermas • Superficial folliculitis • Impetigo • Ecthyma • Furuncle • Carbuncle • Erysipelas • Cellulitis • Paronychia • Staphylococcal scalded skin syndrome • Secondary pyodermas • Management principles

3. INTRODUCTION • Bacterial infection of skin. • Caused by mainly 2 Gram positive organisms: • Staphylococcus aureus: Intact skin • Group A beta-hemolytic Streptococci : Traumatic skin • Other bacteria: • Corynebacteria • Pseudomonas

5. SUPERFICIAL FOLLICULITIS • Infection of the terminal part of hair follicle • Staphylococcus aureus • Scalp and face • Follicular pustules with a rim of erythema

6. IMPETIGO Honey-coloured crusted plaques

7. DEEP FOLLICULITIS • Sycosisbarbae • Furuncle(Boil) • Carbuncle

8. SYCOSIS BARBAE Staphylococcus aureus Erythematous follicular discrete papules or pustules Coalesce Raised plaque, studded with pustules. Beard region in a patient with Sycosisbarbae

9. FURUNCLE • Acute, deep infection of a hair follicle along with perifollicular involvement • Staph aureus. • Tender, inflammatory nodule. • Pus discharge. • Heals with scarring.

10. CARBUNCLE • Deep infection of a group of contiguous hair follicles. • Diabetes, immune-compromised. • Nape of neck, shoulders, hips and thighs. • Pus discharge from multiple points- “Sieve like appearance".

11. ECTHYMA • Diabetes, Immune-compromised • Legs & buttocks • Thick, chocolate coloured, adherent crust with a rim of erythema. • Removal- punched-out ulcer • Heals with scarring.

12. ERYSIPELAS • Group A beta-hemolytic Streptococci • Superficial dermis & lymphatics • Raised plaque • Well demarcated edge • Warm and tender • Edema

13. CELLULITIS • Staphylococcus aureus or Group A beta-hemolytic Streptococci • Deeper dermis & subcutaneous tissue • Diffuse edge- not well demarcated • Warm and tender • Fever • The surface may show focus of pus and necrosis, which may ulcerate

14. PARONYCHIA • Paronychia is the infection of the lateral and/or of the proximal nail folds. • Predisposing factors - Cuticular damage • Overzealous manicuring • Chronic wet work • Classified as: • Acute • Chronic

15. ACUTE PARONYCHIA • Acute onset of pain and erythema of the posterior and/or lateral nail folds. • With subsequent development of a superficial abscess. • Staphylococcus aureusand Group A beta-hemolytic Streptococci Nail with Acute Paronychia

16. ACUTE PARONYCHIA • Treatment: • Topical : • Warm compresses or soaks without abscess • Topical antibiotics • Systemic antibiotics & NSAIDs • Systemic : • Antibiotics • NSAIDs with abscess • Surgical : • Incision and drainage.

17. CHRONIC PARONYCHIA • Etiology : • Damage to cuticle of nail • Chronic Eczema • Chronic Candida infection • Treatment : • Keeping hands as dry as possible • Avoid irritants and allergens • Anti-fungals and corticosteroids

18. STAPHYLOCOCCAL SCALDED SKIN SYNDROME • Infants and children under 5 yrs • Staph. Aureus group II phage type 71 • Exotoxin- Epidermolytic toxin • Febrile and irritable. • Diffuse blanching erythema and flaccid blisters • Perioral involvement • Skin tenderness • Positive Nikolsky sign • Treatment- Parenteral antibiotics

19. MANAGEMENT PRINCIPLES • Identify and assess the predisposing factors : • Poor hygiene • Malnutrition • Recurrent trauma • Diabetes mellitus • Pre existing skin diseases • Congenital and acquired Immunodeficiency • Investigations : • Work up for any predisposing factors. • Smear, Culture and Antibiotic Sensitivity test (SCABS).

20. MANAGEMENT PRINCIPLES : TOPICAL THERAPY • Soaks / compresses : Condy’s solution (KMNO4) • Topical antibiotics: • Mupirocin • Fusidic acid • Framycetin • Nadifloxacin • Bacitracin Topical agents used in the treatment of Pyodermas

21. MANAGEMENT PRINCIPLES : SYSTEMIC THERAPY • Indications of systemic therapy : • Fever, tachycardia • Regional lymphadenopathy • Danger area of face • Pyodermas not responding to topical therapy • Rapidly progressing pyodermas • Available systemic agents : • Semi-synthetic Penicillins • Cephalosporins • Macrolides • Tetracyclines • Quinolones

22. VIRAL INFECTIONS • Molluscumcontagiosum • Human papilloma virus infection • Herpes simplex infection • Herpes zoster infection • Oral hairy leukoplakia

23. MOLLUSCUM CONTAGIOSUM • MC in children • Pox virus- MCV 1-4 • Transmission: • Person-to-person spread • Possibly by fomites • Adults: Sexual transmission • I.P: 2-7 weeks

24. Discrete, smooth, pearly white to flesh-coloredDome-shaped papules • Central umbilication

25. Intracytoplasmic inclusion bodies: Molluscum bodies or Henderson-Paterson bodies Treatment: Curettage 10 % KOH, 0.5 % podophyllotoxin, Imiquimod cream Cryotherapy with liquid nitrogen

26. VIRAL WARTS • Human papilloma virus- more than 100 types • Benign proliferations of the skin and mucosa • Transmission : direct or indirect contact (nail biters, shaving, occupational, swimming pool) • Sexual transmission : genital / perianal wart • Autoinoculation

27. TYPES VERRUCA VULGARIS PLANAR WARTS

28. Filiform and digitate warts • Finger like projection • Periungual warts • Seen in nail biters • Recalcitrant to treatment

29. PLANTAR WARTS GENITAL WARTS

30. Treatment Electrocautery Cryotherapy Topical salicylic acid CO2 laser Podophyllin application for genital warts Risk of development of carcinomas- HPV 16, 18

31. HERPES VIRUS INFECTIONS 1.Herpes simplex virus  1(HSV-1) 2.Herpes simplex virus  2 (HSV-2) 3.Varicella Zoster Virus (VZV) 4.Epstein Barr virus (EBV)- Oral Hairy Leukoplakia 5.Cytomegalovirus (CMV) 6.HHV 6 (exanthem subitum or roseola infantum) 7.HHV-7 8. HHV 8 (Kaposi's sarcoma-associated herpes virus).

32. HSV1 Herpetic gingivostomatitis Cutaneous, oropharyngeal & ocular infections • Recurrent episodes • Triggers • Emotional stress • Illness • Exposure to sun • Trauma • Fatigue Herpes labialis

33. HSV 2 Herpes genitalis Sexual transmission Tender, grouped, discrete vesicles Erythematous base Rupture leaving tiny multiple shallow erosions & ulcerations

34. DIAGNOSIS OF HSV INFECTIONS Tzanck smear: Multinucleated epithelial giant cells • HSV antibody titre : IgG/IgM • Immunofluoroscence, PCR-most sensitive Treatment: • Aciclovir 400mg TID X 7-10 days

35. VARICELLA ZOSTER VIRUS Varicella: Primary infection with a viremic stage Persistence of the virus in dorsal nerve root ganglion Zoster: Reactivation of this residual latent virus. Route of transmission: Droplet infection Infectious period: 2 days- Rash -5 days

36. CHICKEN POX “Dew drops on a rose petal” IP: 14–17 days Prodrome Discrete vesicles on an erythematous base Lesions appear in crops Polymorphism Highly infectious In 2–4 days a dry crust forms

37. Secondary bacterial infection may result in scarring. • Other complications : • Pneumonia : neonates and adults (1/400) • Treatment : • Acyclovir (800mg 5 times a day/1week) for severe cases, high risk individuals and adults (>13 years). • Isolate from immunocompromised.

38. HERPES ZOSTER • Reactivation of latent varicella (chicken pox) infection from the dorsal root ganglia • Unilateral radicular pain • Grouped vesicles on an erythematous base in a dermatomal distribution • Acyclovir 800 mg 5 times a day x7- 10 days

39. Disseminated Zoster • Defined as >20 vesicles outside dermatome. • Elderly or Immunocompromised • Hemorrhagic/gangrenous lesions with outlying vesicles or bullae. • Systemic symptoms include fever, meningeal irritation. Complications: Post-herpetic neuralgia

40. ORAL HAIRY LEUKOPLAKIA • Associated with chronic shedding of EBV in the oral cavity. • Poorly demarcated, corrugated, white plaques on lateral aspect of tongue. • Unlike thrush, cannot be removed by scraping. • Occurs with immunosuppression (esp AIDS) and warrants HIV workup.

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