1) Bacterial Skin Inf

7/29/2019 1) Bacterial Skin Inf

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Bact skin inf


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Bacterial skin inf

Bacterial skin inf is the single most

common diagnosis among those with skin

problems.

The most common bacterial skin inf is

impetigo (superficial pyoderma)


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Group A beta hemolytic streptococcus

commonest cause of skin inf

Colonization of unbroken skin by GABS

precedes pyoderma by 10 days

Intradermal inoculation by insect bite,

scabies or minor trauma leads to

impetigo, ecthyma &cellulitis


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Cutan bact inf

Colonization or pyoderma may predispose

the child to later pharyngeal colonization

with the same strain

Staph aureus spread from the nose to

normal skin and then infect the skin

Clinically the 2 lesions cannot be

distinguished


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S.Pyogenes

Noninvasive strains Invasive trainss

impetigo pharyngitis

nephritogenic

Pyrogenic exotoxins proteinase Spreading factors

Rheumatogenic strain

Rheumatic feverpsgn

Scarlet fever

Toxic shock syndrome

Necrotizing cellulitis/fascitisCellulitis

erysipelas


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Bact skin inf

Those with recurrent inf should be

evaluated for immunodef (neutrophil

dysfunction)


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Impetigo: bullous

non bullous

Non bullous accts for >70% of the cases Tiny vesicle or pustule forms and rapidly

develops into a honey colored crusted

plaque Inf spreads by towels, fingers, clothings


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Contact sports


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Little or no pain, no erythema, no

constitutional symptoms


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Bullous impetigo: infants and youngchildren

Caused by coagulase-positive staph

aureus Flaccid transparent bullae develop on the

skin of face, buttocks, trunk, perineum, &

extremities. Neonatal bullous impetigo can begin in the

diaper area


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Culture of fluid from an intact blister should

yield the causative lesion.

Complications are potential but rare: OM

septic arthritis,pneumonia &septicemia


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Deeper soft tissue inf may occur.

Erysipelas is an acute well demarcated inf

of the skin with lymphagitis involving the

face (ass with pharyngitis) &extremities

(wounds).

The skin is erythematous &indurated

The advancing borders are raised& firm

Ass with fever, vomiting& irritability


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Bact skin inf

CELLULITIS

Strept cellulitis is a painful, erythematous,indurated inf of the skin and subcut tissue

usually follows some injury to the skin

Proteinase producing strain causes amore severe type of necrotizing fascitis or

myositis Also more common in diabetics &

immunocompr


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Bact skin inf

Organisms : St.Pyogenes &S.aureus.

many other org can cause

Presents as local edema, warmtherythema &tenderness.the margins are

indistinct

Regional adenopathy,constitutional S/Sfever, chills &malaise


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Bact skin inf

Complications : OM, sep arthritis,

bacteremia, necrotizing fasciitis

Treatment :specific antibiotics,after proper

evaluation , cultures from the site

In a newborn a full septicemic work up

Cover for strep and staph


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Necrotising Fasciitis (Meleneys

streptococcal gang, Fourniers Is a destructive invasive infection of skin,

subcutaneous tissue &deep fascia with relativesparing of muscle.

Bacteriology could be polymicrobial or

monomicrobial due to group A Beta HaemolyticStrep.

Common sites are genetalia, groin & lowerabdomen.

Pts are unwell, febrilewith areas ofsubcutaneous induration & erythema.Necroticpatches of skin develop.


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Bact skin inf

Treatment is by wide excision of alleffected soft tissue, anibiotics andsupportive treatment. Wide skin deffectswill need surgical procedures to repairthem.

Mortality is high and increases if surgicalexcision is delayed.

Risk factors are D.M., malnutrition,obesity,steroids & immune defecieny.


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Vaginitis :beta hemolytic strep. Are a

common cause of vaginitis in prepubertal

girls.pts usually have a serous discharge&

marked erythema & irritation of the vulvararea,discomfort in walking &urination


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Perianal dis: perianal strep cellulitis

produces local itching,pain,blood streaked

stools, erythema & proctitis.


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Bact skin inf

Staph scalded skin syndrome (Ritter dis)

Agent :staph aureus phage grp 2 str.71,55

Predominantly in infants& children


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Bact skin inf

The scarlatiniform erythema developsdiffusely & is accentuated in flexural &periorificial areas

Conjuntivas : inflammed, discharge maybe purulent

Skin is brightly erythematous& rapidly

wrinkled Severe cases- sterile flaccid blisters &

erosions develop diffusely


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Bact skin inf

Nikolsky sign may be positive(areas of

epidermis separate in response to gentle

shear force

As large sheets of epidermis peel

away,moist glistening denuded areas may

get sec infected ,fluid &electrolyte

imbalances

Healing without scarring in 10 14 days


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Bact skin inf

Antibiotics :orally or parenterally withsemisynthetic penicillinase- res penicillin

Gently moisten the skin and cleanse with

Burow or Dakin soln or N saline Emolient application for lubrication to

decrease discomfort

Recovery is rapid Complications-Pneum,sept,cellulitis,fluid&

electrolyte imbalincreased morbidity


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Bact skin inf

Ecthyma :resembles non bullous impetigoin onset and appearance

Gradually deeper,into the dermis, more

chronic inf and forms an ulcer withelevated margins

Ulcer becomes obscure by a dry heaped

up crust that contributes to the persistenceof inf and scar formation

Spread :autoinoculation


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Lesions may be as large as 4 cm

Frequently on legs

Predisposing factors :as impetigo Causative agent: GABHS (staph is

cultured sec pathogen)

Crust softened by warm compressions &removed by antibact soap

Syst antibiotic tt as in impetigo


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Bact skin inf

Blastomycosislike pyoderma

Exuberant cutaneous reaction to bact inf in

children who r malnourished and

immunosupp

Organism: GABHS,staph aureus


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Various clinical presentations of

Staph. Skin infections.

Boil (fruncle)- is an infection of hair root

including sebaceous gland which usually

proceeds to suppuration and central necrosis.

Boils are common on face, neck and head. Boilsare infrequently associated with overwork, worry,

debelity or may be presenting feature of D.M.

Stye is due to infection of an eyelash follicle, if

suppuration occurs removal of eyelash will allow

drainage.


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Various clinical presentations of

Staph. Skin infections.(ct)

Carbuncle- is an infective gangrene ofsubcutaneous tissue which usually occurs in thenape of neck.

The subcutaneous tissue becomes painful andindurated, overlying skin is red. Unless thecondition is aborted by prompt treatmentextension occurs and after few days areas ofsoftening appear, skin sloughs out anddischarges pus. Usually there is one largecentral slough and surrounded by a rosette ofsmaller area of necrosis. Treatment is as for boil.


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Lupus vulgaris (T.B. of skin)

Occurs between the age of 10-25 face being thesite of election.

One or more cutaneous nodules appear withcogestion of surrounding skin. Extension occurs

very slowly but ulceration is likely to followsooner or later.The resulting ulcer heals in onearea as it expands to another. The mucousmembrane of mouth and nose could be attackedprimarily or as extension from face.

Treatment is by ATT, lesion can be excised ifhealing is slow.

Squamous cell carcinoma tend to occur in scars.


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Lupus vulgaris


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Advance Lupus vilgaris

1) Bacterial Skin Inf

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