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
Polymicrobial including 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
Splenectomy Capnocytophaga
Cirrhosis Vibrio
Palms, soles Syphilis, Rickettsia
Eschar Molds, 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 (purpura fulminans)
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. Surgical exploration or debridement
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. It is similar to cellulitis
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

20. Swollen lymph nodes near the infection (lymphadenopathy)
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)

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 Many patches of impetigo
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 ecthyma The lesion begins as a pustule that later erodes and ultimately forms an ulcer
Typical ecthyma lesions 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