Skin, Soft Tissue, and Bone Infections

1. Skin, Soft Tissue, and Bone Infections IMPETIGO, ABSCESSES, CELLULITIS, AND ERYSIPELA

2. Objectives • Differentiate the various types of skin and soft tissue infections and there clinical presentation • Name pathogens commonly involved in skin and soft tissue infections • Recognize specimens that are acceptable and unacceptable for different types of skin and soft tissue infections

3. Describe the microscopic and colony morphology and the results of differentiating bacteria isolates in addition to other non-microbiological investigation • Discuss antimicrobial susceptibility testing of anaerobes including methods and antimicrobial agents to be tested • Describe the major approaches to treat of skin and soft tissue infections either medical or surgical

4. Considerations in Skin and Soft Tissue Infection • Localization – layer(s) of tissue involved • Localized vs. multifocal • Disseminated vs. symmetrical • Acute, chronic or sub-acute • Deep involvement • Hematogenous vs. exogenous • Host factors, exposures

5. General Rules in Skin Infection • Pustules, tender painful papule or nodule with fluctuance • Pyogenic esp. Staph • Spreading erythema, painful , recent onset • Strep, Pasteurella • Bites • Cat (Pasteurella), dog (Capnocytophaga), human (Eikenella) • Linear nodules • Tularemia, Mycobacterium, Sporothrix, Nocardia • Vesicles • Herpes, Rickettsialpox

6. Systemic toxicity, pain out of proportion to appearance • Necrotizing fasciitis • Bullae • Vibrio, Capnocytophaga, Campylobacter • Gangrene • Polymicrobialincluding Clostridia, enteric GNR • Eschar • Molds, anthrax, tick borne, septicemia • Purpura • Meningococcus, Strep, Staph • Petechiae • Rickettsia, CMV,EBV, HIV (acute)

7. Classic associations in Skin Infection Finding Organism(s) • Mastectomy Group A strep • Fish Tank M. marinum • Fresh water Aeromonas • Thorn, moss Sporothrix • Neutropenic, moist area Pseudomonas • Neutropenic, tender nodules Candida • SplenectomyCapnocytophaga • Cirrhosis Vibrio • Palms, soles Syphilis, Rickettsia • EscharMolds, anthrax, Rickettsia • Lymphadenopathy Bartonella, Tularemia

8. Skin Infection: Geographic Factors • Lyme disease • Blastomycosis • Yersinia pestis • Coccidioides • Ehrlichia • Vibrio, mycobacteria • Leishmania

9. Fever and Rash: Life threatening Associations • Petechial lesions - meningococcal, rickettsial sepsis • Mucosal involvement – Stevens-Johnson syndrome • Bullae – Toxic epidermal necrolysis, Vibrio • Purpura – meningococcus, staph, strep, or pneumococus (purpurafulminans) • Ecthyma gangrenosum – Gram negative sepsis

10. Miscellaneous clues to Etiology of Skin infection • Urticaria – hepatitis B (autoimmune reaction) • Slapped cheek, sock and glove purpura – Parvovirus • Hemorrhagic pustules – Neisseria • Nail puncture foot – Pseudomonas • Amoxicillin – EBV • Chronic severe atopy, severe burns – HSV • Intrathoracic or intraabdominal involvement – Actinomycosis, TB • Underlying osteomyelitis – S. aureus, Bartonella • Lung and /or CNS involvement – Nocardia, endemic mycoses, mycobacteria

11. Fever and Rash: Important Considerations • History must include risk factor assessment – concurrent diseases, medication, travel, occupational/recreational exposure, animals • Thorough exam including entire skin area, mucosa, lymph nodes • Infectious and non infectious diseases can coexist • Skin biopsy for culture and histology rarely contraindicated • Acute retroviral syndrome self-inflicted lesions often not considered

12. Adequate differential diagnosis requires • History • Patient’s immune status • The geographical locale • Travel history • Recent trauma or surgery • Previous antimicrobial therapy • Lifestyle • Animal exposure or bites • Physical Examination • Severity of infection

13. Investigation • CBCs, Chemistry • Swab, biopsy • Radiographic procedures • Level of infection and the presence of gas or abscess • Surgical exploration or debridement • Diagnostic and therapeutic

14. RAJAN S Cleveland Clinic Journal of Medicine 2012;79:57-66

15. Impetigo Impetigo is a common skin infection Facial impetigo

16. Causes, incidence, and risk factors • Caused by streptococcus or staphylococcus bacteria • MRSA is becoming a common cause • The skin normally has many types of bacteria on it • Intact skin is an effective barrier • keeps bacteria from entering and growing in the body • When there is a break in the skin • bacteria can enter the body and grow there • causing inflammation and infection

17. Breaks in the skin may occur with: • Animal bites • Human bites • Injury or trauma to the skin • Insect bites • Impetigo may also occur on skin where there is no visible break • It is most common in children • particularly those in unhealthy living conditions

18. In adults • it may follow other skin disorders or a recent upper respiratory infection • such as a cold or other virus • It is similar to cellulitis • but it only involves the top layers of the skin • Impetigo is contagious, meaning it can spread to others • You can catch this infection if the fluid that oozes from the blisters touches an open area on your skin

19. Symptoms • A single or possibly many blisters filled with pus • easy to pop and when broken leave a reddish raw-looking base (in infants) • Itching blister • Filled with yellow or honey-colored fluid • Oozing and crusting over Blister on foot caused by wearing flip flops

20. Rash • may begin as a single spot • but if person scratches, it may spread to other areas • Skin lesions on the face, lips, arms, or legs, that spread to other areas • Swollen lymph nodes near the infection (lymphadenopathy) A diffuse rash on the back of a male

21. Signs and tests • Diagnosis is based mainly on the appearance of the skin lesion • A culture of the skin or lesion usually grows the bacteria Streptococcus sp. or Staphylococcus sp. • The culture can help determine if MRSA is the cause • specific antibiotics are used to treat this infection

22. Treatment • The goal is to cure the infection and relieve the symptoms • A mild infection may be treated with a prescription antibacterial cream • More severe cases may require antibiotics, taken by mouth • Wash (do not scrub) the skin several times a day • preferably with an antibacterial soap • to remove crusts and drainage

23. Expectations (prognosis) • The sores of impetigo heal slowly and seldom scar • The cure rate is extremely high • the condition often comes back in young children

24. Complications • Kidney failure • post-streptococcal glomerulonephritis • rare • Many patches of impetigo • in children • Permanent skin damage and scarring • very rare • Spread of the infection to other parts of the body • common

25. Prevention • Prevent the spread of infection • use a clean washcloth and towel each time • do not share towels, clothing, razors, and other personal care products with other family members • wash hands thoroughly after touching the skin lesions • Good general health and hygiene help to prevent infection

26. Thoroughly clean minor cuts and scrapes with soap and clean water • You can also use a mild antibacterial soap • Impetigo is contagious, so avoid touching the draining (oozing) lesions

27. Infected impetigo

28. Bullous impetigo • Mainly seen in children younger than 2 years • Involves painless, fluid-filled blisters • mostly on the arms, legs, and trunk • surrounded by red and itchy (but not sore) skin • The blisters may be large or small • After they break, they form yellow scabs

29. Bullae Bullous impetigo

30. Ecthyma • Ecthyma is a skin infection similar to impetigo • It is often called "deep impetigo“ • because it occurs deep inside the skin

31. Causes, incidence, and risk factors • Ecthyma is most often caused by the bacteria Streptococcus sp. • Sometimes, Staphylococcus sp. bacteria causes this skin infection • The infection may start in skin that has been injured due to a scratch or insect bite • It often develops on the legs

32. Symptoms • The main symptom of ecthyma • a small blister with a red border • may be filled with pus • The blister is similar to that seen in persons with impetigo • the infection spreads much deeper into the skin • After the blister goes away, a crusty ulcer appears

33. Signs and tests • You can usually diagnose this condition simply by looking at patient skin • In rare cases • the fluid inside the blister may be sent to a lab • or a skin biopsy may be done

34. Treatment • You will usually prescribe oral antibiotics • Very early cases may be treated with topical medications • More advanced forms may need intravenous antibiotics • Placing a warm wet cloth over the area • can help remove ulcer crusts • You may recommend • antiseptic soap or peroxide washes to speed recovery

35. Expectations (prognosis) • Unlike impetigo • ecthyma can sometimes result in scarring

36. Complications • Spread of infection to other parts of the body • Permanent skin damage with scarring

37. Prevention • Carefully clean the skin after an injury • such as a bite or scratch • Avoid scratching or digging at scabs and sores

38. The stages of ecthymaThe lesion begins as a pustule that later erodes and ultimately forms an ulcer Typical ecthymalesions of the lower extremities

40. Skin abscess • A skin abscess is a build up of pus in or on the skin • An abscess is a collection of pus (neutrophils) that has accumulated within a tissue • an inflammatory process in response to • an infectious process • or other foreign materials • It is a defensive reaction of the tissue • to prevent the spread of infectious materials to other parts

41. Causes • Skin abscesses are common • They occur when an infection causes pus to collect in the skin • Skin abscesses may occur after: • A bacterial infection (often staphylococcus) • A minor wound or injury • Boils • Folliculitis • A skin abscess may occur anywhere on the body • The problem affects people of all ages

42. Symptoms • Symptoms may include: • Fever or chills, in some cases • Local swelling around the infected spot • Hard of tissue (induration) • Skin lesion that may be an open or closed sore, or domed nodule • Redness, tenderness, and warmth in the area • Fluid drainage

43. Exams and Tests • You could diagnose the problem by looking at the affected area • The drainage from the sore may be sent to the lab for a culture • This can help identify the cause of the infection

44. Treatment • You can apply moist heat • to help the abscess drain and heal faster • DO NOT push and squeeze on the abscess • The health care provider may cut open the abscess and drain it • You may need to describe antibiotics by mouth to control the infection

45. Outlook (Prognosis) • Most skin abscesses can be cured with proper treatment • Infections caused by MRSA are do not respond to regular antibiotics and need special medicines

46. Possible Complications • Spread of infection in the same area • Spread of the infect in the blood and throughout the body • Tissue death (gangrene)

47. Prevention • Keep the skin around minor wounds clean and dry to prevent infection • Call your health care provider if you notice signs of infection • Take care of minor infections promptly

48. Abscess Back Abscess