Skin and Soft-Tissue Infections

Skin, Soft Tissue, and Bone InfectionsIMPETIGO, ABSCESSES, CELLULITIS, AND ERYSIPELAObjectivesDifferentiate 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 surgicalConsiderations in Skin and Soft Tissue InfectionLocalization 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 InfectionPustules, tender painful papule or nodule with fluctuance Pyogenic esp. Staph

Spreading erythema, painful , recent onsetStrep, Pasteurella

BitesCat (Pasteurella), dog (Capnocytophaga), human (Eikenella)

Linear nodulesTularemia, Mycobacterium, Sporothrix, Nocardia

VesiclesHerpes, RickettsialpoxSystemic toxicity, pain out of proportion to appearance Necrotizing fasciitis

BullaeVibrio, Capnocytophaga, Campylobacter

GangrenePolymicrobial including Clostridia, enteric GNR

EscharMolds, anthrax, tick borne, septicemia

PurpuraMeningococcus, Strep, Staph

PetechiaeRickettsia, CMV,EBV, HIV (acute)

Classic associations in Skin InfectionMastectomyGroup A strepFish TankM. marinumFresh waterAeromonasThorn, mossSporothrixNeutropenic, moist areaPseudomonasNeutropenic, tender nodulesCandidaSplenectomyCapnocytophagaCirrhosisVibrioPalms, solesSyphilis, RickettsiaEscharMolds, anthrax, RickettsiaLymphadenopathyBartonella, Tularemia

FindingOrganism(s)7Skin Infection: Geographic FactorsLyme disease

Blastomycosis

Yersinia pestis

Coccidioides

Ehrlichia

Vibrio, mycobacteria

LeishmaniaFever and Rash: Life threatening AssociationsPetechial 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 infectionUrticaria 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 ConsiderationsHistory 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 consideredAdequate differential diagnosis requiresHistoryPatients immune statusThe geographical localeTravel historyRecent trauma or surgeryPrevious antimicrobial therapyLifestyleAnimal exposure or bites

Physical ExaminationSeverity of infection

InvestigationCBCs, ChemistrySwab, biopsy Radiographic proceduresLevel of infection and the presence of gas or abscess

Surgical exploration or debridementDiagnostic and therapeutic

13

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

Impetigo is a common skin infection

Facial impetigoCauses, incidence, and risk factorsCaused by streptococcus or staphylococcus bacteriaMRSA is becoming a common cause

The skin normally has many types of bacteria on it

Intact skin is an effective barrierkeeps bacteria from entering and growing in the body

When there is a break in the skinbacteria can enter the body and grow therecausing inflammation and infection Breaks in the skin may occur with:

Animal bitesHuman bitesInjury or trauma to the skinInsect bites

Impetigo may also occur on skin where there is no visible break

It is most common in childrenparticularly those in unhealthy living conditions

In adultsit may follow other skin disorders or a recent upper respiratory infectionsuch as a cold or other virus

It is similar to cellulitisbut 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 skin18SymptomsA single or possibly many blisters filled with puseasy to pop and when broken leave a reddish raw-looking base (in infants)

Itching blisterFilled with yellow or honey-colored fluidOozing and crusting over

19Rashmay begin as a single spotbut 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 testsDiagnosis 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 causespecific antibiotics are used to treat this infection21TreatmentThe 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 drainage22Expectations (prognosis)The sores of impetigo heal slowly and seldom scar

The cure rate is extremely highthe condition often comes back in young childrenComplicationsKidney failurepost-streptococcal glomerulonephritisrare

Many patches of impetigoin children

Permanent skin damage and scarringvery rare

Spread of the infection to other parts of the bodycommon24PreventionPrevent the spread of infection

use a clean washcloth and towel each timedo not share towels, clothing, razors, and other personal care products with other family memberswash hands thoroughly after touching the skin lesions

Good general health and hygiene help to prevent infection25Thoroughly 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

26

Infected impetigo

Bullous impetigoMainly seen in children younger than 2 years

Involves painless, fluid-filled blistersmostly on the arms, legs, and trunksurrounded by red and itchy (but not sore) skin

The blisters may be large or small

After they break, they form yellow scabs28

BullaeBullous impetigoEcthymaEcthyma is a skin infection similar to impetigo

It is often called "deep impetigobecause it occurs deep inside the skin

30Causes, incidence, and risk factorsEcthyma 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 legsSymptomsThe main symptom of ecthymaa small blister with a red border may be filled with pus

The blister is similar to that seen in persons with impetigothe infection spreads much deeper into the skin

After the blister goes away, a crusty ulcer appearsSigns and testsYou can usually diagnose this condition simply by looking at patient skin

In rare casesthe fluid inside the blister may be sent to a labor a skin biopsy may be done

TreatmentYou 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 areacan help remove ulcer crusts

You may recommendantiseptic soap or peroxide washes to speed recovery34Expectations (prognosis)Unlike impetigoecthyma can sometimes result in scarringComplicationsSpread of infection to other parts of the body

Permanent skin damage with scarringPreventionCarefully clean the skin after an injurysuch as a bite or scratch

Avoid scratching or digging at scabs and sores

Typical ecthyma lesions of the lower extremities

The stages of ecthymaThe lesion begins as a pustule that later erodes and ultimately forms an ulcer

Skin abscessA 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 toan infectious processor other foreign materials

It is a defensive reaction of the tissueto prevent the spread of infectious materials to other parts40CausesSkin 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 injuryBoilsFolliculitis

A skin abscess may occur anywhere on the body

The problem affects people of all ages41SymptomsSymptoms may include:

Fever or chills, in some casesLocal swelling around the infected spotHard of tissue (induration)Skin lesion that may be an open or closed sore, or domed noduleRedness, tenderness, and warmth in the areaFluid drainageExams and TestsYou 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

TreatmentYou can apply moist heatto 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 infection44Outlook (Prognosis)Most skin abscesses can be cured with proper treatment

Infections caused by MRSA are do not respond to regular antibiotics and need special medicinesPossible ComplicationsSpread of infection in the same area

Spread of the infect in the blood and throughout the body

Tissue death (gangrene)PreventionKeep 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 Abscess48