Download Skin and Soft-Tissue Infections

Skin, Soft Tissue, and Bone
Infections
IMPETIGO, ABSCESSES, CELLULITIS, AND ERYSIPELA
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
 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
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
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
 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)
Classic associations in Skin Infection
Finding
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Mastectomy
Fish Tank
Fresh water
Thorn, moss
Neutropenic, moist area
Neutropenic, tender nodules
Splenectomy
Cirrhosis
Palms, soles
Eschar
Lymphadenopathy
Organism(s)
Group A strep
M. marinum
Aeromonas
Sporothrix
Pseudomonas
Candida
Capnocytophaga
Vibrio
Syphilis, Rickettsia
Molds, anthrax, Rickettsia
Bartonella, Tularemia
Skin Infection: Geographic Factors
 Lyme disease
 Blastomycosis
 Yersinia pestis
 Coccidioides
 Ehrlichia
 Vibrio, mycobacteria
 Leishmania
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
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
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
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
 Investigation
 CBCs, Chemistry
 Swab, biopsy
 Radiographic procedures
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Level of infection and the presence of gas or abscess
 Surgical exploration or debridement
 Diagnostic and therapeutic
RAJAN S Cleveland Clinic Journal of Medicine 2012;79:57-66
Impetigo
Impetigo is a common
skin infection
Facial impetigo
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
 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
 In adults
 it may follow other skin disorders or a recent upper
respiratory infection
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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
Symptoms
 A single or possibly many blisters filled with pus
 easy to pop and when broken leave a reddish rawlooking base (in infants)
 Itching blister
 Filled with yellow or honey-colored fluid
 Oozing and crusting over
 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)
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
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
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
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
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
 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
Infected impetigo
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
Bullae
Bullous impetigo
Ecthyma
 Ecthyma is a skin infection similar to impetigo
 It is often called "deep impetigo“
 because it occurs deep inside the skin
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
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
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
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
Expectations (prognosis)
 Unlike impetigo
 ecthyma can sometimes result in scarring
Complications
 Spread of infection to other parts of the body
 Permanent skin damage with scarring
Prevention
 Carefully clean the skin after an injury
 such as a bite or scratch
 Avoid scratching or digging at scabs and sores
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
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
Causes
 Skin abscesses are common
 They occur when an infection causes pus to collect in the skin
 Skin abscesses may occur after:
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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
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
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
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
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
Possible Complications
 Spread of infection in the same area
 Spread of the infect in the blood and throughout the
body
 Tissue death (gangrene)
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
Abscess
Back Abscess